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5 Answers

How to insulate and sheathe my walls?


I am renovating a 1920s home in Vermont. Its a four square New-Englander with a hip roof.

Right now we have the old plaster stripped off, and lath exposed. What I would like to do is;

1- Blow in cellulose insulation behind lath.
2- Plaster over the lath.

In Green building techniques | Asked By Justin | Feb 7 17
6 Answers

Optimum insulation thickness

I would like to seal up the crawlspace walls on my house (in zone 3B). I cannot locate a contractor willing to spray any of the low-GWP closed cell foams and there are too many obstacles to allow for a quality cut-and-cobble job. Wall assembly is full-dimension 2x4, (no sheathing), lap siding, housewrap, then cedar shingles. So, assuming my only option is high-GWP closed cell foam, what is the minimum I can safely specify? Is there any scenario where open cell spray foam would be reasonable? The crawlspace is dry, even in this 2.2x typical rainfall winter.

In General questions | Asked By Keith Richtman | Feb 7 17
9 Answers

How to insulate a screened porch floor

I am looking to insulate the floor of a 3-season porch that is outfitted with removable sashes that will be removed for the entire summer season, thus exposing the floor to some blown-in rain. The sashes will be reinstalled in the fall so that the porch can be used in the fall and spring and will be opened up to the main house to benefit from the heating system in the house.

In Energy efficiency and durability | Asked By Elizabeth Slotnick | Nov 28 16
15 Answers

Best heat for the money

We just built a new home in new england with a new heating system. House was built tight within the new stretch codes. The heat system has 2 unico I series heat pumps with three unico air handlers. My back up (aux) heat is a 5 section buderus boiler. So there is a hot water coil in all three of the unico AH's for the aux heat. The data I got from the unico rep is as follows.

EER- 7.45
SEER - 14
HSPF- 8.35

So from info I found on this site to the the COP I divide the HSPF by 3.412 This gives me a approx COP knowing that the HSPF is based on seasonal data.

COP- 2.44

In Energy efficiency and durability | Asked By user-6740240 | Feb 3 17
1 Answer

In the blown-in category: does it matter what's on top of what?

In the blown-in category: does it matter what's on top of what? I.e., can you blow cellulose into an attic on top of fiberglass? Does it matter if cellulose is on top of fiberglass?

In General questions | Asked By Brian Lengel | Feb 8 17
3 Answers

Vents to roof or wall?

Need some advice. I have to run new vents for a dryer 4", a bathroom vent 4", and my kitchen downdraft vent 6". All are nearly in the middle of my house so the closet location to vent to is my roof, which I'd rather not do since it is a tile roof and introducing more spots for leaks cannot be good, and all vents will be in the most visible part of the roof from the ground.

In Mechanicals | Asked By Jimmy Black | Feb 8 17
6 Answers

HELP sizing a mini-split for my house!

Hi all! This is my first question but I've been reading this site obsessively for the past few weeks, especially all of the info about mini-splits (BTUs, efficiency, cold weather performance, sizing, modulation, etc.). I'm purchasing two mini-splits for my new-to-me old house, and I've been struggling with sizing. It's crunch time since I need to make a decision by tomorrow morning, so I was hoping for some advice. I'll give as many relevant details as I can below, and am very grateful for any input!


In General questions | Asked By NewOldHousePhilly | Feb 7 17
16 Answers

HTP Phoenix Light Duty paired with Lifebreath Clean Air Furnace (downdraft)

I want to replace the atmospheric water heater (interior to my house) with sealed combustion. I also wanted to replace the 80% furnace that sits right beside the WH interior to the house. I learned early from GBA that inside combustion is to be avoided.

Fast forward...I am looking at the HTP Phoenix Light Duty + Lifebreath CAF (downdraft). I am in the Seattle, WA area in a 1950's rambler.

In Mechanicals | Asked By S K | Jan 11 17
5 Answers

Is there a GBA article that just explains the stack effect?

Something i can link to others who know nothing about how it works and explains the basics.
I did a quick search without success

In Energy efficiency and durability | Asked By Alan B | Jan 31 17
3 Answers

Open cell spray foam under roof deck

A couple years ago we converted our vented attic to an unvented/conditioned attic with open cell spray foam applied under the plywood roof deck. We even installed an HVAC vent in the attic to keep the RH in the attic similar to the rest of the house. So far everything seems fine but I've recently read about issues with open cell under roof decks, including one article on this website. I live in climate zone 4, asphalt roof over plywood deck. Should I be concerned about having a wet roof deck?

In Energy efficiency and durability | Asked By Michael Mohr | Feb 7 17
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