Planning my basement theater space in New England (only need heat down there). Have forced air system through rest of home and really don't want to tap system for basement - will simply use some electric baseboards as I do not need a signficant temp rise.

However, I am concerned about getting fresh air into the basement space.

I am considering using a Heat Recovery Ventillator just for the basement. It will provide plenty of fresh air for the space and should work just fine with the electric heat.

Simple ductwork also, I will use a single return and maybe just a few supplies. I only have two finished rooms down there.

Anyone have experience with this type of configuration?

db

Careful. You'll need some way to get cool air into the room, even in NE type climates. The equipment alone cranks out a ton of heat. Add a few bodies and the space will get uncomfortable very quickly.

Anyone have experience with this type of configuration?
db

Send a PM to BasementBob to get his attention I'm pretty sure he has one.

Thanks - will PM him.

Basement theater room will be about 400sq. ft and well insulated. Will be adjacent to another 1000 sq ft of finished basement space which will be adjecent to another 1000 sq ft of unfinished space.

The only equipment in the theater room will be the projector. (Oestensibly, there will also be the heat produced by the voice coils in the speakers, but this should be minimal) However, there will be up to 8 people in the room - there may be a need for cooling potential. In its unfinished state, the basement is always a steady 60 degrees or so. I suspect that even when the walls are insulated, the floor will remain a strong heat sink.

HVAC guy coming tuesday - have lots of questions....

db

Here's an HRV that works well. http://www.broan.com/display/router.asp?ProductID=100080

You'll regret not have A/C in your well insulated home theater. 8 people means 4000 BTU's hour plus what the projector is generating. That insulation is doing as much to keep the cool out as it is keeping the heat in.

The HRV is a nice solution for fresh air, but they do not come cheap.

I'm trying a cheaper, but hopefully still effective, method of getting fresh air into the HT. I have a 150 cfm fan in the equipment room behind the theater. The equipment room is sealed, except for a register to the theater room connected by a baffle box such as is shown in the attached picture. The other end of the theater room has another such box opening to the unfinished basement. This should work for getting fresh air into the room (calculated pressure drop is fairly low, but the fan manufacturers don't specify flow rate vs. pressure drop), and hopefully it boxes are effective as reducing sounds transmission through the hole in the wall.

I'm in the same boat as to wondering whether additional HVAC for the theater will be necessary. My quipment is in a separate room and I'm hoping that 100 cfm of fresh air from the rest of the cool basement will be sufficient to keep the room comfortable. I have a sneaking suspicion that Dennis is correct and that I will wish for additional cooling in the room. I'm planning for a mini-split system if that is the case, but I figured I'd save some money and try it without first.

No question Dennis is correct. You'll want A/C or end up with an extremely seasonal theater.

Also keep in mind that the whole point of an HRV (or ERV) is to absorb the heat from the exiting air and transfer it to the incoming fresh air so that you are getting fresh air that is as close to your ambient room temperature as possible. It is designed to maintain temperatures - not change it.

If the intent is to try and use fresh air as a semi-substitute for cooling, you don't want an HRV, you'd be better off with a straight transfer of theater air for outdoor air (assuming the outdoor air is cooler than your theater). Theoretically, you could thermostatically control a fan that will effectively utilize the cold New England winter air as an adequate cooling source - but it would still be a seasonal solution.

I have a mini-split heat pump that works nicely. I have noticed a 30% reduction in electric bills after switching from electric baseboard heat. The model I use is from Mitsubishi

My primary goal for the HRV is fresh air, not heat/cool. Especially in a (dry to my knowledge) basement, I want the space to smell fresh and not accumulate the musty smell many finished basements do gain over time. I though by introducing fresh air and exhausting the stale air, I would acheive this.

Now for heating and cooling....

Heating is easy - electric baseboard. But what about cooling - what about all those BTUs generated by the people and projector in the theater space?

The HRV will supply air to the theater space, but will return air from the rest of the finished basement. I will also have a passive vent from the theater space into the rest of the finished basement. Thus, the HRV will essentially be circulating thermal air energy (but actually introducing fresh air at the same time) through the 400 sq ft theater into the 1000 sq ft. rest of the basement. I am postulating that this will be enough circulation between the theater and the main space to keep undesired heat from building in the theater. I do not believe that 8 people in the theater plus equipment would overheat 1400 sq ft. of space (there is another 1000sq ft of unfinished space down there also, but not directly part of the air circulation from the HRV). I was considering the smallest of the HRVs, about 70 CFM - perhaps I should upsize one step to 150. In fact, I could run the 150 on low most of the time and tie the high speed control input to the theater lighting control to activate when occupied.

If this strategy fails, I can always add a mini split system.

Another interesting thought - how about a freestanding AC in the theater space (one of the R2D2 like freestanding models) but venting into the finished basement space. Essentially it will just move the heat out of the theater as needed.

db

You will definately need A/C in the summer as the HRV will be bringing in hot humid air adding to the heat gain load.

Check the specs. on HRV's you will find that they are not very effecient.

You will need 21 CFM per person as per ASHRAE indoor air quality guidlines.

Bill

Adding a mini-split system may solve the problem of cooling, but you will introduce a new set of problems such as introducing a higher noise floor to the room.

The main advantage of a mini-split is you don't need to accommodate ductwork and it requires minimal space because there's no air handler (well, there is, but you know what I mean). If you have a bordering full basement to play with and, presumably, easy access to cut in supplies and returns into your theater space, there's no reason not to just put in a standard split system. Then noise is a non-issue - as is the termperature coming in from the HRV.

An HRV (heat recovery ventilator, aka air-to-air-exchanger) between two rooms in a basement is not what you want. It will level the oxygen between the two spaces, and pretty much level the humidity as well, but it won't remove any heat from the home theatre (it's designed to keep cold areas cold, and warm areas warm), and it's expensive. An HRV with three of it's four pipes inside, and the fourth outside, doesn't make much sense either (over or under pressure -- either will give you no air flow through the HRV).

If all you want to do is move air between two rooms, consider an in duct fan tied to the projector on signal. That at least will level the temperature and oxygen and sweat-smell between the two rooms (both rooms will get hot and humid together), and it's a lot cheaper than an HRV.
One additional room is not enough of a 'heat and humidity sink' for a soundproof room with a few people and a plasma/projector and a 100w 7.1 amplifier.

A drawing of what you're thinking of might be handy. Including dimensions, chairs, and possible equipment. Maybe someone here can do a BTU calculation and CFM calculation from that.

Not a recommendation, but one varient that's cheap would be to try to use the whole house as a 'heat and humidity sink', and take a little advantage of central air conditioning:
a) assuming your home has central air conditioning
b) have a return air duct from the HT to the main furnace return air duct, close to the main register for the house, and close to the house thermostat. Thus if the furnace fan is off, conduction will let the heat from the HT rise to the thermostat, but if the furnace fan is on, it'll be sucked down to the furnace.
c) have the forced air duct from the HT attached to the main trunk forced air duct close to the living room registers, so that when the furnace is off it can suck air from the living room, and when the furnace is on it'll get air from the furnace
d) have an in-line duct fan in the duct from the living room main trunk, and have that in-line duct fan come on whenever the projector is on.
e) ensure that you can get to the not-in-the-room side ducts, in case you need to upgrade in the future (AC), and that the ducts are big enough to handle the slow (quiet) CFMs you need.
f) A problem with this design is the room gets extremely little air when the projector is not on, and it's not balanced air nor balanced cooling (not a zone).

BTW, in the spring/fall I tend to run my HRV 24/7.
But in the summer I have the HRV on a timer so that it only runs from midnight until 6am -- because that's when it's coolest outside, and the least moisture per cubic foot of air outside, and otherwise my home gets quite humid.

Kevin_Wadsworth:

Have you tried measuring the 'wind speed' of a fan driven air out of your baffle box? I'm surprised it doesn't stall.

Something like 6' of 6" round metal pipe, fan, 6' of 6" round metal pipe, put a wind speed tester at the output of the pipe. Then duct tape the output of the round metal pipe to your baffle box, and put a wind speed tester at the output of your baffle box.

(I once had a similar, but larger scale plan)

dbbarron:

(You might want to update your profile and 'State' your location. It has useful effects on advice/comments. Your first post says you're in New England, but that's not really handy for next-day thoughts without re-reading the entire thread every day.)

Another interesting thought - how about a freestanding AC in the theater space (one of the R2D2 like freestanding models) but venting into the finished basement space. Essentially it will just move the heat out of the theater as needed.I think I know of someone who was considering that for a music studio this month. Except they put the R2D2 in the other room (less noise, less stuff in the important room), and they were venting out a window to outside (rather than making the nearby room a sauna).


You want
a) cool air (your equipment and people are hot, you need to cool them off)
b) fresh air (you consume oxygen)
c) dry air (you emit moisture)
d) forced air and return air vents -- in the room

To get that you need a certain cubic feet of air flow per minute, and a certain number of tons of cooling.

The best 24 page description of HVAC requirements for studios I've ever seen is in
Home Recording Studio Build It By The Pros by Rod Gervais (http://www.amazon.com/dp/1598630342).

dbbarron:

This thread Studiotips: Ventilation design concerns (http://forum.studiotips.com/viewtopic.php?t=2948) might be interesting reading.
Ignore everyone in that thread except 'Rod Gervais', who's the only one who knows what he's talking about. There's also a spreadsheet referenced in that thread that you might be able to use to do some HVAC calcs.

Will check out the link. Thanks.

I may have been somewhat unclear regarding the HRV ducting -

I will use the conventional HRV outside supply/return to the outside. Interior, to/from the HRV interior supply/return; I will supply air to the theater and return air from the adjacent finished basement space. There will be a passive duct between the theater and adjacent finished basement to permit airflow. Thus, I am essentially circulating air through the theater and finished basement and introducing fresh air at the same time.

Per the 21CFM per person spec, I should use the 150cfm HRV models and tie high speed (150 cFM) into an output of the theater lighting control to activate when the theater is occupied. Thus, fresh air, check.

Heat is baseboard electric, check.

Cool and humidity remains the issue. I intend to include a humidifier in the finished basement space - due to the circulation, this should take care of the whole theater/finished space issue - humidity, check.

So, Cool remains - will have to think about this. Wonder if an R2D2 style portable AC exists that you can duct out of and I could put in a closet adjacent to the theater. Exhaust it to the home exterior, blow the cool air into the theater.

db

Take a look at this unit.

http://www.sharpusa.com/products/ModelLanding/1,1058,1858,00.html

I could place this in the rear of the theater and vent it outside (possibly through the same duct as the HRV). It would cool and dehumidify the theater.

Spec states 36 db in low cool mode. This is quite good.

I do know that some of these portable units will also heat (they simply run the heat exchanger in the other direction) - Don't know if these are as quiet.

It would also be nicer if it was 'built in'. Wonder if I could build a nook for it with a louvered opening.

Of course - small mini-split is not much more!

http://www.brilliantstore.com/mini_split_air_conditioners_amcor_uchw_h09af2.html

But I still need the fresh air.

db

You'll get very little cooling out of that unit at the 36 db low cool mode.

Is there a reason you are shying away from a standard split system? Seems like you're anticipating exerting a lot of effort to adapt less-than-ideal products to your application in the hopes that it partially (possibly) solves your problem.

humidity remains the issue. I intend to include a humidifier in the finished basement space - due to the circulation, this should take care of the whole theater/finished space issue - humidity, check.Backwards.
You may want a dehumidifier. It's people that are humid. It's amazing how much humidity 8 people put out in a closed warm room in an hour.
And in the summer the HRV will increase the humidity even further.

yes - dehumidifier - typo

The portable dehumidifiers I have
http://www.bobgolds.com/dehumidifier/home.htm
make 66 dB(C) of noise, and emit a slight warmpth in the air.

I think this is what you're describing in text.

http://www.bobgolds.com/dbbarron/dbbarron.gif.

Yes - that's it (except I'd consider the portable AC in the theater, not the outside room).

Anyhow, some quick calcs - theater has

400 sq ft of floor perhaps R3 away from a 58 degree sink - at approx 15 degree delta, I would require 400/3*15 or 2000BTUs in to maintain 72 degrees just from the floor.

left Side (your pic) and rear wall is much less significant as they are well insulated.

Right well is not significant as this is uninsulated and part of the air exchange

top theater wall is essentially uninsulated - call it R5 (unfinished space behind screen wall - 1" of fiberglass for acoustics) - So, 110/5*10 (partially burried) = 200 btus

Thus, to maintain 72 degrees, we need about 2200 BTUs - i.e. it will overheat with 8 people.

BUT - air is exchanged with the whole finished space. Since the floor dominates heat loss, Thats 1400/3*15=7000 BTUs - we have some surplus, but must now add in all the equipment which we can call 500-700W or about another 2000BTUs. Close one.

In most cases there will only be 2 people in the theater. Sometimes 4. Infrequently 8.

I think I should insure that I have capability to add AC should it be needed. I think fresh air is a must (HRV or exchange with the house).

Some additional facts:

Right now it is about 80 degrees out (9:30pm) - was very hot today - about 90 peak.

Just measured basement floor at 61-62 and basement walls scale from 62 at floor level to 72 at top of foundation wall (90" up).

I consider this just about worst case for my location.

So, my above calcs are off at worst case by about a third.

Kevin_Wadsworth:

Have you tried measuring the 'wind speed' of a fan driven air out of your baffle box? I'm surprised it doesn't stall.



The room in under construction (the picture of the baffle box was taken just a week ago), so I haven't measured airflow yet. I certainly will once construction is done.

I calcualted the pressure drop to be just under 0.5 inches of water. The fan I have is listed at 150 cfm at 0.1 iwc and 127 cfm at 0.25 iwc. I have no idea how fast it drops after that, but if it's linear, I should still be getting ~90 or so CFM from the fan.

Time will tell whether the fan is powerful enough - if not I can add some booster fans to help push the air through.

I zoned my current AC system. One for the theater & lobby area, one for the upstairs. I had a few estimates done and basically using that info wound up doing it myself. Saved a bunch. I think it's the best way to go and cost about as much as a good mini-split unit and/or trying to figure all the other options out. Cost ran about $1300-$1400 for materials to set it up for the 2 zones.

I have a carrier infinity system for the main house which is easily zoned (great system also). However, since cooling will be the issue for the HT, and we heat about 9 months of the year, there is a large likelihood that I would have to cool the theater, but heat the house. The zoning of a single system would not work well in this scenario.

The more I think about it, merely a circulating fan between the HT and main finished basement space (150cfm or so) may be the best option - perhaps using an HRV, perhaps not. Also insure that the main space is properly dehumidified.

If use dictates that we will need AC in the theater space, add mini-split or portable (insure I have adequate access to do this when designing space).

dbbarron,

Im in New England as well, Mass.

My home was built in 06 with Central Air. The blower is in the attic with supply lines coming down from second floor to first floor ceilings and didn't make it down to the basement unfortunately.

I considered a mini split for the basement but wanted each area to be comfortable so I would have needed a unit that could handle 3 zones at least. At that point the cost starts to be pretty comparable to a traditional system. I had a friends cousin come and do all the measurement and calculations for me to determine what I would need which I knew was a minimal system but he also determined that I needed 5 supply lines at 6" each, he also solved my heating needs since I have a hydronic boiler by adding a heating coil to the blower. No need for baseboards now, saving me some money, time and effort and it only added a couple 100 bucks to the overall cost. He told me my whole basement area will be heated in about 5 minutes tops.

Now I know you want to probably do this as simply as possible as did I, and often as I went down to the basement to do some work in the spring I said to myself "it's really cool down here, do I really need HVAC" and would grab a sweater. But, after 5 minutes of light work im HOT and ripping my sweater and shirt and go down to a t-shirt. That's me by myself cant even imagine a bunch of my buddies down there just hanging out playing video games and pool (not yet, anyways).

If your gonna do it, now is the time to do it right. Ultimately you want your area to be comfortable and a place you can enjoy without feeling stuffy.

Wow, 9 months out of the year heating, huh? You must be more North than I am :)

I was a little concerned about that too. There are low-temp limits where you can't run AC cooling. But I figure we set the heat to 70-72 in the winter. So if the theater gets warmer than that, circulating the air with the AC fan would cool it down. At the very least it would keep things circulating.

It would be nice to incorporate a way to use the colder outside air for cooling in the winter. That will be Ductwork Phase II. ;)

Andy

I'm near boston. Ok 7-8 months. (late sept through april)

HVAC contractor looked at situation.

Recommended, consistent with the forum, mini-split for the space; both theater and playroom, 2 zone unit. Has to price it out, but he did know that a 17 SEER Fujitsu single zone heat/cool was $3400 installed including electrical. I imagine the second zone would add another $2k or so. This is way out of anticipated budget, but as ti takes care of heat, cool and dehumidification in an efficent and proper manner, might be worth considering.

Heat pump in new england would work out to about the same cost of operation as natural gas. He though it would work all the way down to NE temperatures, I'm not so sure.

Other option would be to use electric baseboard in playroom and mini-split only in theater.

Interestingly enough, he did not seem at all concerned with getting fresh air into the theater, just conditioning the air in there.

Most contractors don't address fresh air simply because of the expense involved. It isn't something that many homeowners are willing to pay for, so they don't spend a lot of time trying to push it.

Still think a traditional split system makes far more sense. 2 zones and keep the initial costs down by only ducting the theater - then just dump the second zone into the playroom space at the air handler.

"Most contractors don't address fresh air simply because of the expense involved. It isn't something that many homeowners are willing to pay for, so they don't spend a lot of time trying to push it."

He really didn't seem all that familiar with the notions of fresh air; just conditioning - told me you don't need much fresh air if conditioned properly. My gut still tells me it can't hurt to install a low CFM HRV circulating between the theater space and playroom space.

"Still think a traditional split system makes far more sense. 2 zones and keep the initial costs down by only ducting the theater - then just dump the second zone into the playroom space at the air handler."

I agree, budget permitting, but please explain "only ducting the theater....dump the second zone into the playroom". I'm a bit confused as there are no 'ducts', just the room unit. I either put in one (theater only) or two (one in theater, one in playroom).

db

> re: the HRV.

The lack of familiarity generally is simply a result of the company not training on or pushing a product. That's fine, but the smart thing is not to comment at all rather than make a statement like "if conditioned properly, it is unnecessary". That's like saying if your water is heated to the appropriate temperature, filtration is unnecessary. Apples and oranges.

Typically, indoor air (regardless of temp/humidty) is about 20 times more polluted with contaminates than outdoor air. The tighter the house, the more the need/benefit to an HRV or ERV. Having said that, I haven't personally put one in my home - but if the price/value/benefit equation makes sense to you - you should definitely not let someone talk you out of it. At least not based on uninformed generalizations made by the service tech.

> Standard split system
With a standard split system, you have the condenser outside and the air handler in your basement. If you want two zones, you just add a zoning system and two dampers and thermostats. If you wanted to keep the initial costs down, you could run the supplies from the theater's damper and the return(s) from the theater back to the air handler. For the second zone (playroom/rest of basement) you could just run a big 14" (or whatever the proper size is) flex duct up to the ceiling and dump the supply air out into the basement. The closer the air handler is to the theater (minding the sound issues) the less expensive any ductwork costs are.

Cost should run much less than $5400 if there is minimal ductwork labor.

Andy - Can you give an idea what all was involved in doing that? How tough was it to get things set up properly? Do you have any references you used for info?

Thanks!
Craig


I zoned my current AC system. One for the theater & lobby area, one for the upstairs. I had a few estimates done and basically using that info wound up doing it myself. Saved a bunch. I think it's the best way to go and cost about as much as a good mini-split unit and/or trying to figure all the other options out. Cost ran about $1300-$1400 for materials to set it up for the 2 zones.

Sure - here goes...

I have a 3-ton forced air central HVAC system from Carrier and it runs on gas. The zoning process wasn't really difficult. The main thing to be concerned with is moving the right amount of air through the system - regardless of what zone is calling for AC or heat. You don't want to freeze your coils or overtemp your burner. I did some research here to learn about zoning. As I understand it EWC is one of the better manufacturers of zoning equipment. I also googled for anything related to HVAC zoning.

After learning about it I called a couple AC contractors for estimates. Since I kinda knew what I was talking about I asked specific questions about system capacity, how they are going to handle the zone airflow, where are the ducts going to go, and - most important - can they give me a detailed written estimate. One contractor gave me details, one didn't. Here's a tip, ask if they could just design the system for a nominal fee so you can do the work.

I basically used the detailed estimate as a guide and bought the parts - dampers, ductwork, control panel, etc. I'll break it down in sections:

Ductwork: I found a good website to order ductwork (it was easier than trying to find a local supplier willing to sell retail) and bought all the ductwork from them. Some stuff I got at Lowes or Home Depot. Based on the detailed estimate, I added a new trunk off the AC plenum for all the supplies to the theater, lobby, and bathroom. Off the trunk I have 2 supplies to the theater, one to the bathroom, and 2 to the lobby and hallway that leads to the bathroom. I have two returns in the theater and one in the lobby that are connected to the existing return trunk. I used flex duct and metal pipe for the supplies and flex for the returns. Code in my town says no more than 15 feet of flex duct for supplies. Metal ductwork comes in halves and has to be assembled. Another tip - get Nashua 2" silver foil duct tape labeled "UL-181" from Home Depot. Lowes didn't have it. That tape is code approved for metal duct and flex duct. Most of the other rolls of tape you find at the home center aren't allowed per code. The duct pretty much snaps together but use #8 sheetmetal screws and tape for assembly.

Dampers: I got mine on e-bay - dampersdirect, I think. They aren't as fancy as the ones from EWC but they were only $100 each. I needed 3 for my system - two to put in the existing supply trunk and one for the new trunk. You just cut a rectangular hole in the side or bottom of the trunk, slide it in and secure it with screws and tape. There are different kinds of dampers - Power open & spring close, spring open & power close, and power open & power close. Match the kind you use with the controller. Each damper is uses a two-wire connection to the control panel. I'm only using two zones - upstairs and downstairs with the downstairs thermostat in the theater. Basically when the theater calls for ac/heat, the two dampers in the existing trunk close and the damper in the new trunk opens. When the upstairs calls for ac/heat the dampers reverse - new trunk closes and existing trunk opens.

Zone control panel: I got a EWC NCM-300 ($245 on-line). It does up to 3 zones only (not expandable). It is very flexible on the type of dampers you can use with it and it has a temp sensor to protect your coils. The upstairs and theater thermostats get connected to the controller along with the ac unit and the dampers. Very simple wiring using common hvac labeling. You can download the panel instructions from the EWC website.

Ok, so that was more than a rough idea. :)
Believe it or not the hardest part was putting the dang insulation on the new trunkline! I had to have an S-shape then a curve coming off my plenum and that was a bear to wrap.

So here are some websites:

EWC Controls (http://www.ewccontrols.com/)
Zone controller (http://acforsale.com/online/advanced_search_result.php?keywords=ncm-300)
Ductwork (http://www.audubonsupply.com)

I can post some pics if you want.

Hope this helps :)

Andy

It might be worthwhile to contact some local HVAC distributors once you get a list together and see if they'll do a cash sale to non-contractors. Most have a policy that they don't sell to homeowners, but it's just a policy. ;) If you own a business of any kind, most will sell to a business without much hassle.

I know sheet metal ductwork is much more prevalent in the NE, but don't discount using flex duct. It is readily available and simple to work with for all of your runs. It also makes for easy connections to round zone dampers (stick with power close dampers). If you can wire a thermostat (and follow instructions), you can wire a zoning system.

Wow, thanks for all the detailed info!

Here is another crazy thought.....

I will only need cooling on occasion in the 400 sq. ft. space.

I can heat with electric baseboard and ventilate to the adjacent 1000 sq ft space with a small fan.

How about using a portable AC vented into the adjacent space!

That large space can certainly sink the heat load, and it is simplistic. I'm only paying to move some heat across a small differential - should be quite efficient.

Will use AC with separate drain so I don't introduce humidity issues. (sharp)

db

Not to de-rail but just a quick side question for Basement Bob.

What are your thoughts on an ERV vs. HRV? In your situation you mentioned humidity problems during summer days, would an ERV help that or is it not worth the extra $100 bucks or so bucks the ERV costs?

Radryan:
I know how an HRV works, but I don't know how an ERV works.
You might be able to run an ERV more than I run my HRV, because an ERV supposidly handles humidity better.
My HRV has a little drain out the bottom, that's supposed to drain moisture (a good thing in summer, perhaps a bad thing in winter) -- but really not much comes out of there that I've noticed.

I don't have these, but the 81% heat exchange and the photo of the ERV internals were interesting:
http://www.healthyhouse.com/product_avsduo.html
http://www.drirotors.com/erv.htm

ERV's use a desicant coated heat wheel that rotates the heat transfer surfaces between the two air streams, thereby transfering heat (both sensible and latent)by forced convection. HRV's use a fixed heat exchanger and transfer only sensible heat by conduction( the heat exchanger is a vapour barrier and therfore no latent heat is transfered). HRV's usually don't produce moisture in the drain during the summer. The exhaust air from your home is not cold enough (75F) to create condensate conditions in the fresh air, it would have to be very hot and humid outside 90F 60+%RH. Depends where you live I guess.

HRV's reduce indoor humidity in the winter, thats a good thing. Reducing moisture build up on windows helps prevent mold growing conditions.

IF the ERV is only 100 bucks more, I would go for it. In the long run it will pay off, even if it is only 69% eff. in the summer.

Bill

Time to resurrect this thread :)

I was at a party the other night hosted by a neighbour ... they basically invited a few of the neighbours and some family for a get together ... and one of them I met is a commercial HVAC contractor.

Background - developing entire basement with 22 X 11 games room, hallway 15 X 4, Gym 10 X 13, bathroom 8 X 8 and Theater 23 X 14.5

House has 2 X furnaces ( one each for main & second floor ), 2 X Air Conditioners ( one each for main & second floor )

Since my theater build is currently just before drywall stage I asked him about whether in my case I would have sufficient heating/cooling for the theater ... his suggestion was to add a ERV vented to exterior dedicated to the theater and still go with a standard air suuply/return from the main ducting ... he also suggested to leave the ERV running on low ( 50 cfm ) or depending on how much the theater gets used to have it activated by the projector so it turns on or off depending on whether the room is in use.

I did a search for ERV on this site and got this thread ... it has been over a year since the last post so what has everyone found to be the best way to deal with heating & cooiling the space in the theater ... keep in mind I am in Canada so think NORTHERN climates :D