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Grimrace
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| 05/18/2009 1:28 AM |
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Greetings. Long time reader, first time poster.
Getting ready to finally start the design work on our dream home, to be built in Victor, Idaho. Elevation is around 6200 feet.
The climate in this region is such that, imo, air conditioning is a total waste, given that there are only 5-10 a days a year that I might wish I had it, let alone actually need it. Plus, having come from southern California (Bakersfield) and being used to very hot summers, there's not much in Victor that's going to beat me down during the warm months.
Since I'm mostly sold on a hydronic heating/gypcrete solution for our home, I'm wondering if it's possible to forsake any sort of forced air/duct work. I don't really want any sort of forced air, for both noise and allergy reasons. However, especially with tight envelope homes, I understand that ventilation of some sort is required (bad air out, good air in), but what's the best way to achieve that given my hoped-for-but-perhaps-unrealistic plan?
Rough floor plan is 1400 sf main floor, 1400 sf basement, and 800 sf second story (center loft, guest bedrooms on either side). I'm planning on hydronic installation in both the basement and main floor (gypcrete for both)... and not too sure about the second floor yet.
Thanks for any responses, I'm continually impressed by the knowledge of many of the posters here.
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BadgerBoilerMN
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| 05/18/2009 6:34 AM |
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| Any competent designer will consider the complete envelope and specify an ERV for IAQ. |
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MA
www.badgerboilerservice.com |
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jonr
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| 05/18/2009 7:53 AM |
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You can do a limited amount of hydronic cooling (just keep the floors above the dewpoint). Add a 21 seer dual zone mini-split to a couple of rooms + a whole house attic fan and I expect that you will never miss those noisy ducts.
If you get heat pump mini-splits, there are days when they will outperform geothermal.
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BadgerBoilerMN
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| 05/18/2009 8:31 AM |
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| Whole house attic fans are no longer used. Radiant floor cooling is nearly exclusive to residential applications in very dry climates e.g. AZ,NM parts of TX thus the need for an experienced designer. |
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MA
www.badgerboilerservice.com |
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jonr
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| 05/18/2009 10:00 AM |
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Whole house attic fans work great when you want outside air. Just open a few windows and get a good breeze.
Ceiling fans work well when you don't want outside air (AC is running or hotter outside than inside).
In most climates, dew point is almost never above the 68-70F that you can use for limited radiant cooling. But check for your climate.
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NRT.Rob
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| 05/18/2009 10:06 AM |
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opening windows to get outside air? In winter? that's not exactly indoor air quality. That's barely breathing, and a recipe for mold/moisture and health problems.
HRV/ERV or "exhaust only" ventilation with controlled inlets and exhaust fans are the only real solutions. balanced ventilation is really the only way to ensure good air quality in a home, throughout the home, year round.
people greatly underestimate the need for real ventilation. I am excited to check out new ECM motor ventilators to start saving more energy too.. |
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-=Northeast Radiant Technology=-
NRTradiant.com |
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BadgerBoilerMN
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| 05/18/2009 10:07 AM |
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| Have you installed (or designed) a lot of whole house fans or radiant cooling jobs? |
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MA
www.badgerboilerservice.com |
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Grimrace
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Posts:6
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| 05/18/2009 10:58 AM |
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Posted By NRT.Rob on 05/18/2009 10:06 AM
HRV/ERV or "exhaust only" ventilation with controlled inlets and exhaust fans are the only real solutions. balanced ventilation is really the only way to ensure good air quality in a home, throughout the home, year round.
Ah, NRT.Rob. Been following your posts here and on LHOTI for quite some time.
I've read about HRV/ERV (as in, I know what they stand for), but what exactly is entailed with the installation? Where do the controlled inlets and exhaust fans (usually) go?
And... yes... I really don't want to open the windows too often on winter days in Victor.  Though I do love cool night air in the bedroom!!
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Dana1
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| 05/18/2009 11:09 AM |
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Whole house fans tend to be big infiltration leaks, yet they still seem to have a following. They're usually net annual energy loss, but yes, they DO suck a lot of ventilation air through when you want to max out the air exchanges.
At 6.2k' in ID you just don't NEED much cooling if you can control summertime solar gain with overhangs & exterior shading, and have a decently tight & well insulated house with some thermal mass (I'd say a slab heating system would be good enough). With low daytime gains even a small bit of nighttime ventilation would be good for more than 99% of the time- forget about adding the complexity of radiant cooling (which would work well at that climate and altitude, but is just SO unnecessary.) In high-dry Victor/Driggs it reliably drops below 70F overnight, even on days when it hits 100F during the day, usually with cooling mountain breezes flowing into the valleys after sunset. (Drop-dead gorgeous mountains there- I fully understand the attraction! It's definitely NOT Bakersfield CA, eh!) If you're energetic enough to a few windows after the temps drop below the indoor temps, and leave 'em closed during the day you'll be good to go. Since it's new construction you can manage the glazing and orientation to tweak optimal winter/summer solar gains, unless you have such "to die for" view out the southern or western aspect that you just HAVE to over-glaze it, and not obscure it with shade trees or long overhangs. |
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Blueridge company
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| 05/18/2009 11:27 AM |
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Plan on heat on all three floors, you will regret it otherwise, at 6,000 feet , dead winter -35 the loft will get chilly.
Air to air heat exchangers are fairly straight forward. All flex duct work and not perticularly expensive. usualy in a house your size you would have make up air in the bed rooms and an equal number of exhaust in the bath, kitchen and laundry, make up exhaust in the basement to move air as well. your bath fan and range fan are separate.
Forget cooling, you are from Bakersfield (read 98+ in sumer), open the windows Alpine air is cool.
Allergies and air filtration, this is a key reason you would consider an additional expense on a more substantial air movement system. Consider a Hi-V system, this type of unit can be fitted with a very competent air filter (Merv 11, UVC light, Titanium plate filter). Now we are talking real air filtration and movement. The HRV is then applied to the return air side. This is a considerably more expensive system but if air quality is a real health issue than the end justifies the means. With this appliance you also open the option to add cooling if you can't live with out it in the future. Odds are you would install this in the basement, venting through the floors or walls. Now you can also get best air movement in the whole house as well.
Simple answer to the question, Yes you can heat hydonicaly in floor with out any other system, put in an HRV.
Dan
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Dan
BlueRidgeCompany.com |
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jonr
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| 05/18/2009 11:39 AM |
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For the clueless, whole house fan is in response to air conditioning, not indoor air quality. And if you can't figure out how to seal and insulate a fan hole in your ceiling, you shouldn't be involved in design.
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NRT.Rob
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| 05/18/2009 11:57 AM |
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Jonr, before you sling stones, perhaps you care to re-read the first post, in which no mention of cooling was made other than to dismiss it as totally unnecessary, and a question about indoor air quality was asked.
Then re-read your first response. While you talk cooling for some reason, since the thread has nothing to do with cooling, you also say he can get rid of his ducts, which would seem to respond to the actual question being asked... which was, of course, how to get IAQ without ducts.
Grim: I would not worry about air filtration to a high level unless you have medical conditions that require it. Ever. HRV/ERV are ducted systems but as Dan has said the ductwork is typically flexible though it can always be a challenge figuring out where to put them.
Personally I would prefer room by room through the wall HRV/ERV units, but there aren't many to choose from, so ducts it is. Someday...
for exhaust only systems, the makeup inlets are basically "controlled holes" in the wall. the exhaust fan can be bath fans with a central control/timer, or a dedicated exhaust fan that also does bath exhaust, or what have you. I have always preferred HRV/ERV units, however the new ECM units are sure to make the energy comparison beyond reproach... IMHO ;). However they are new. |
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-=Northeast Radiant Technology=-
NRTradiant.com |
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Grimrace
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Posts:6
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| 05/18/2009 2:25 PM |
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Posted By Dana1 on 05/18/2009 11:09 AM
(Drop-dead gorgeous mountains there- I fully understand the attraction! It's definitely NOT Bakersfield CA, eh!)
Ain't that the truth!
Thanks much to everyone for their responses, I greatly appreciate it. I'm certainly more informed now, and I like to have at least a basic knowledge about such things before I start signing checks or swiping the card.
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Dana1
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Posts:702
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| 05/19/2009 9:20 AM |
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The size of the ducts in HRV systems may be quite modest compared to the image in your mind when you think "ducts". (6-7" diameter trunks w/4 & 5" branches are typical.) The flow rates are pretty low compared to the chilled blast of the AC systems you may be accustomed to as well. Under-ventilated tight houses can develop mold issues- HRVs tend to be the cure, not the cause of allergy symptoms. (Running them off humidistats, not just duty-cycle controllers can be important in some installations.)
If noise is a major issue for you, set some upper limit specs for the ventilation units- under 30dBA is very good, but under 25dBA is GREAT. (If specified in sones: <1.0=good/<0.6=great.) 30-35dBA is generally considered quiet enough for sleeping areas, but it never hurts to go lower. It should go without saying (but experience proves otherwise) that all joints in ductwork should be sealed with mastic. Not only does the proper seal preserve the design function, it can make as much as 15dBA difference in noise level without the whistle & hiss of air leakage. (Retrofit mastic sealing made a ~20dBA difference on the antique heating/AC ducts in my house, but typical new-construction would have started out with somewhat lower leakage.) Limiting the number of of turns also makes a difference.
If radiant floor is out of the question for the upper story, low-temp panel radiators are still pretty nice, respond quickly, and can deliver the the at radiant-floor temperatures. |
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jmagill
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Posts:237
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| 05/19/2009 10:17 AM |
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| You could investigate this option. use them in the bathrooms.
http://www.kitchensource.com/bathroom-fans/fv-04ve1.htm |
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Grimrace
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Posts:6
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| 05/19/2009 10:22 AM |
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Posted By Dana1 on 05/19/2009 9:20 AM
The size of the ducts in HRV systems may be quite modest compared to the image in your mind when you think "ducts". (6-7" diameter trunks w/4 & 5" branches are typical.) The flow rates are pretty low compared to the chilled blast of the AC systems you may be accustomed to as well. Under-ventilated tight houses can develop mold issues- HRVs tend to be the cure, not the cause of allergy symptoms. (Running them off humidistats, not just duty-cycle controllers can be important in some installations.)
If noise is a major issue for you, set some upper limit specs for the ventilation units- under 30dBA is very good, but under 25dBA is GREAT. (If specified in sones: <1.0=good/<0.6=great.) 30-35dBA is generally considered quiet enough for sleeping areas, but it never hurts to go lower. It should go without saying (but experience proves otherwise) that all joints in ductwork should be sealed with mastic. Not only does the proper seal preserve the design function, it can make as much as 15dBA difference in noise level without the whistle & hiss of air leakage. (Retrofit mastic sealing made a ~20dBA difference on the antique heating/AC ducts in my house, but typical new-construction would have started out with somewhat lower leakage.) Limiting the number of of turns also makes a difference.
If radiant floor is out of the question for the upper story, low-temp panel radiators are still pretty nice, respond quickly, and can deliver the the at radiant-floor temperatures.
Re: Size of the ductwork - You're right, I had imagined something much larger. 6-7" is likely something I could live with, combined with the low flow rates you mentioned. Am I right in thinking that a HRV system also helps keep condensation off the windows? Hmm, I wonder if the vents that go in the bathrooms could be incorporated into my ventilation strategy...
Noise isn't so much an issue as it's on my wish list. For some reason, the idea of a perfectly quiet house in a mountain setting has always appealed to me; a house that silently sits among the trees and shares the forest with them. Idyllic, of course. The only noises I want to hear are the owls at night, the hawks at day, the wind through the trees, etc. Mechanical noises... not so much. So while it may be a pipe dream, I'm still striving to make it as ultra quiet as possible.
I'm reluctant to do radiant on the upper story if only because that area won't be used too much. The loft, from time to time, the guest room but 5 times a year (and likely only once in winter, it's a hardly soul who wants to come visit Victor in February), and the second bedroom/office, a panel radiator or something similar seems plenty. To do full radiant up there would seem like a waste of material... mainly, the material dollars in the bank account!
Thanks again, the input is greatly appreciated.
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Grimrace
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Posts:6
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| 05/19/2009 10:29 AM |
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Posted By jmagill on 05/19/2009 10:17 AM
You could investigate this option. use them in the bathrooms.
http://www.kitchensource.com/bathroom-fans/fv-04ve1.htm
Oooooh, back-end of an F-14 look. Full afterburner. Dig.
They look a bit pricey, though I guess that would depend on how many of them I'd need.
Thanks!
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Dana1
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Posts:702
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| 05/19/2009 11:00 AM |
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It's common in HRV ducting schemes to pull the majority of the exhaust air out of bathrooms & kitchens, duct supply air to all rooms, and dispense with separate kitchen & bath fans. (Sometimes the HRV is under humidistat control in the bathrooms to guarantee it gets under 60% RH after someone takes a shower). This approach works best in dry climates- I suspect it'll work for you. (Other places might still need separate bathroom ventilation.)
The F-14 engines on that single-room HRV live above the ceiling line when installed, so you don't really get the thrill of watching the after-burners in operation... :-)
If there's any wind in the trees, the refrigerator is running, or your spouse/dog is snoring, you won't hear the HRV unless you're listening intently if it's below 25dBA. Standard 'merican refrigerators are typically in the~40-50dBA range, but "quiet running" types or small ones can be in the 30dBA range. Figure every 6-10dB lower sounds half as loud. 25dBA is pretty low- I'll bet there are some old-skool motor-drive electric clocks almost that loud. :-) |
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Blueridge company
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Posts:211
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| 05/19/2009 1:15 PM |
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Here is a link to the whole house type, there is an install manual related to forced air system but it is simple to run as a stand alone unit, equal number of intake to exhaust outlets, similar pipe lengths to balance.
Dan
http://www.blueridgecompany.com/radiant/hydronic/666/generalaire-heat-energy-recovery-ventilators |
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Dan
BlueRidgeCompany.com |
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Grimrace
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Posts:6
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| 05/19/2009 2:29 PM |
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Posted By Dana1 on 05/19/2009 11:00 AM
It's common in HRV ducting schemes to pull the majority of the exhaust air out of bathrooms & kitchens, duct supply air to all rooms, and dispense with separate kitchen & bath fans. (Sometimes the HRV is under humidistat control in the bathrooms to guarantee it gets under 60% RH after someone takes a shower). This approach works best in dry climates- I suspect it'll work for you. (Other places might still need separate bathroom ventilation.)
The F-14 engines on that single-room HRV live above the ceiling line when installed, so you don't really get the thrill of watching the after-burners in operation... :-)
If there's any wind in the trees, the refrigerator is running, or your spouse/dog is snoring, you won't hear the HRV unless you're listening intently if it's below 25dBA. Standard 'merican refrigerators are typically in the~40-50dBA range, but "quiet running" types or small ones can be in the 30dBA range. Figure every 6-10dB lower sounds half as loud. 25dBA is pretty low- I'll bet there are some old-skool motor-drive electric clocks almost that loud. :-)
Ah, good news on the involvement of bathrooms/kitchen in the HRV scheme. Just knowing those afterburners are up there, quietly doing their thing, would be satisfaction enough. =) Thank you for the dBA examples, that definitely puts it in perspective. I'd try to stuff it in some remote corner of the house, or of course where it could operate most efficiently. Hopefully those two are roughly the same... Dan/Blueridge, thanks for the whole house version, the units are much smaller than I would have thought... nice! |
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