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14 Answers

Solar hot air preheat for HRV/ERV

Has anyone seen a successful approach to using a solar hot air collector to preheat the intake air for an HRV / ERV?

It would be fairly simple to bypass the collector when preheat wasn't desirable.

One major concern is regulating temperature so excessive heat doesn't compromise the HRV / ERV.

It seems like it could be an ideal way to temper incoming air on cold, clear Colorado days (climate zone 6B), and get a little extra solar gain.

Asked By Pat Kiernan | Aug 17 16
13 Answers

Sizing a whole-house fan for a larger house?

Hi All,

Considering a whole house fan for our soon-to-be-built "Pretty Good House" in Central KY, zone 4A.

The house is on the larger size, and the calculations for the type of WHF I need are off the charts in terms of what is available in the marketplace (I assume), what I have attic venting for, etc.

So, keeping in mind that the fans in the marketplace are about, say, one third or one half the size it needs to be sized correctly, is there still a benefit to including one in our build?

Asked By Clay Whitenack | Jun 21 16
11 Answers

Critique my Mini Split placement options

Hi all,

I am down to crunch time and getting close to pulling the trigger on HVAC strategy. Before I "bite the bullet", I want one last pep talk. I think I have the upstairs figured out, but I'm concerned exactly as to where to place my heads.

I have posted two mini split layouts below. Let me know what you think. I have included the room to room BTU loads as well.

Asked By Clay Whitenack | Aug 19 16
5 Answers

Polyiso sandwich with synthetic underlayment

I'm located in Central Texas (China Spring, TX) and am building a house with my wife. The house was originally started by the previous owners and we are replacing and redoing quite a bit of it at the start. We are doing the majority of the work ourselves (taking forever) and we are at the point of finishing the roofing

Asked By Jacob Cox | Aug 24 16
0 Answers

What to do about stairs and doors during basement energy retrofit?

Good evening,

Asked By adam stanton | Aug 24 16
0 Answers

Wall Detail for Exterior foam and .....(wait for it).....SHINGLES

We're in the process of building a home in MA and committed to external foam on walls and roofs

There's a ton of great detail here on exterior foam and I've followed / read it and Martin's other posts on rainscreens.
We're still struggling with the best practical assembly for traditional shingles rather than clapboard.

There are the 3D mesh rainscreens that Martin suggests in his "All About Rainscreens" article, but if those are used, how do you provide a nailbase for the shingles? If thye are used is thee sheathing put at the outside?

Asked By Edward Cambridge | Aug 24 16
5 Answers

Spray foam the ceiling joists vs. the back of the roof sheathing?

Is there ever a time when an attic space is so large that it is better to spray the ceiling joists rather the backing of the roof sheathing?

(No cathedral or vaulted ceilings…)

The home is ~6000 sq ft under roof (including garages) the builder is thinking that it is better to spray the ceiling joist since the attic space is so large.

(There are areas were the ridge row is ~15+ ft above the ceiling joists.)

His logic is why  do I want to cool the attic and that my electric bill will be higher since I’m heating/cooling a larger area.

 

Asked By Cynthia Richards | Aug 23 16
9 Answers

Help me bust this comical Manual J calculation

Calling all energy nerds. Double check my math. I have a manual J calc in my hands with some weird results. I could go over every little error (some obviously intentional), but you have seen these kinds of things before. What I want to talk specifically is heat loss through the wall. His report does not show the design temps, so I am trying to work backwards through the calculations to figure it out. That's where I need your help to double check my thinking.

The inputs:

Asked By Clay Whitenack | Aug 23 16
2 Answers

Paint removal using soda blasting off of soft brick is damaging the brick exterior.

Thanks for all the informative info on this site. I'm owner of a 100 year old former wagon factory built with soft brick - known in Wisconsin as Cream City brick which is notoriously soft. The previous owner had painted the building many times. As discussed, trapped moisture in the brick causing spalling, etc. Right now we are trying to gently remove the paint using a soda blaster. Soda blasting is supposed to be one of the gentlest of methods of paint removal.

Asked By Brian Burns | Aug 24 16
3 Answers

New roof cost? Upgrading from a low slope to a steep slope

I live in Ontario Canada. Im considering all my options to improve my old home's attic space. You see, we get lots of ice damming each winter. The existing roof has a 3/12 pitch along with an 8/12 cathedral. Im wondering if it is cheaper to have a contractor build a new steeper pitch roof over my existing (or remove the existing for the steeper one).

Asked By Jake Rabe | Aug 21 16
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