6600 Btu/hour for a 1,300 sq ft home
I want to build my next home using prefabbed SIPs (structural insulated panels) and use several best practices in design to maximize the energy efficiency of the home. The house would be in Charlotte, NC so they are no super cold winters or very rare 100 degree days.
This is an example of a super insulated home:
Realistically speaking, aside form running a hair dryer, do they make HVAC equipment to handle such tight homes? I have found tons of literature on building techniques etc, but very little information on sizing and specialized HVAC equipment for super-tight, super insulated homes. The only place I know to start is a Air Exchanger Energy Recovery Ventilator to help get fresh air into the conditioned space. Have you guys found any good resources?
They make central A/Cs as small as 1 ton.
Check out post by "paul42"
His house is around 4000 sq ft. and uses a 2 ton A/C.
I think that the EERVs are not cost effective, especially in an air tight house. Humidity control will be important, and EERV's just can't help much there.
Originally Posted by samskaff
Your HVAC energy costs will be too low for the EERV to ever pay back in its lifetime. The embedded energy in the EERV will exceed any energy savings you might get from it.
I recommend a blower door test to make sure that your final result is as tight as you are planning for.
I recommend whatever brand one ton HVAC unit you can find with a good installer. You want a variable speed blower, and a Honeywell IAQ thermostat for humidity and fresh air control. The fresh air intake should go directly to the return air of your HVAC unit. The bathroom exhaust, dryer exhaust, and kitchen hood exhaust will provide exhaust paths - whether the blowers are on or not. Put decent one way dampers on all exhausts.
If someone desires a steady supply of fresh air, the erv is the way to go
We may just have to agree to disagree on this one. I believe that it will be cheaper in the long run to just put a blower on a fresh air intake and condition the air. The difference in energy costs between the two approaches will never pay for the ERV.
Originally Posted by Carnak
Further north, an HRV 'might' be cost effective.
I do not really expect an electrical engineer to agree with me
I am all for intermittent ventilation paul.
But if you want a constant, steady supply of fresh air, your lowest energy costs will be an ERV.
Up in Canada HRVs are very effective and have been in use for about 30 years now.
Last edited by Carnak; 08-07-2008 at 01:08 PM.
Show how do you keep fresh air in the house conditioned?
How does the fresh air control systems work? Are they just setup on a timer? Do they condition the air before circulating it through the house or just filter the air? I thought a an EERV was a best practice for getting fresh air into a home, I guess I still have a lot to learn.
they can operate on a timer, they can operate continuously, they can be interlocked to run whenever your heating or cooling system runs. In the winter they can also be controlled to run via a dehumidistat.
Do a little more research on the SIPs !!
With SIPs panels you need to control the humidity to match the outside... Yeap..
Originally Posted by Carnak
I have personally seen it happen.. sheetrock busted at the seems... they may have fixed it by now... Make sure before you jump
You have a piece of OSB on the inside exposed to 40%-50% RH....
Than you have a piece of OSB on the outside exposed to 80%-100%....
Find out about the up charge for the electrical and plumbing.
If you plan on using siding.... go look at SIPs house with siding
Make dang sure the foam and OSB is borate treated !!!
One county here in Ga will not allow SIPs... better check with the codes folks as well