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2 Answers

Trying to make final selections on materials

Need some advice. Got some before from here but can't recall login so posting new thread to ensure I am covered.
- I am in zone 6. Minimum code R-15 required.
- I am finishing a walkout basement.
- Have poured concrete walls with exterior R-5 XPS rigid on walls.
- No history of water, never damp basement
- Was encouraged to do R-13.1 foil faced on interior walls and frame in front. Problem - cannot find foil faced anywhere local that is 2" thick R-13.

Question:
- Can I do R-10 XPS frame in front

In General questions | Asked By ZDude | Mar 16 17
4 Answers

Need sizing advice on a minisplit unit

I installed a Mitsubishi FH12NA in summer of 2014 when they first came out. I live in inland San Diego, and it can get hot, like 10-15 degrees hotter than the coast.

My condo is a studio and is only 420 sq ft. I'm on the upper unit of 2 stories. I face East and South. I have a skylight and dual-pane windows. Building is 1978 construction.

My Mitsubishi is weak. I set the temp and it will barely do anything. I have to set the temp to 61 and manually put the fan on high for it to do anything. Even "powerful" mode is weak.

In General questions | Asked By aypues | Mar 16 17
35 Answers

Inexpensive, efficient HRV?

I just saw the posts about the Panasonic Intelli Balance 100 ERV. Does anybody make a similar HRV? Something with a price point under $1,000, good efficiency and at least 50+cfm airflow? A unit like that would make me reconsider an exhaust-only system.

The closest I've found are the Braun HRV160 ECM units.

--John

In Mechanicals | Asked By John Ranson | Mar 12 17
9 Answers

Basement wall assembly in climate zone 3A

Hi folks,

I'm finishing my homes basement and have been reading on GBA and FHB around the issues and approaches for resilient and efficient assemblies. Below are some facts about my situation:

Climate Zone 3A, new house built in 2016, daylight basement with 3 poured concrete walls and one 2x6 framed, wall height 9'-6".

In Energy efficiency and durability | Asked By Jamie Royal | Mar 19 17
6 Answers

Insufficiently thick exterior foam: Remove, increase, ignore?

Hi there,

I've been reading the articles on GBA about exterior foam and I think mine is too thin to keep the sheathing above the dew point. I'm wondering your opinions as to the best remedy. I'm assuming that removing or increasing the thickness will both be expensive. I believe my wall assembly is risky, but have no evidence it is actually a problem. Given that I'm wondering if the best course of action is to live with it. Here are the details:

- 2 x 4 walls
- .75" polyiso
- Plywood sheathing
- No rain screen
- Stud cavities filled with fiberglass batts

In Energy efficiency and durability | Asked By Jeremiah Breer | Mar 19 17
10 Answers

ERV vs. HRV Efficiency - Humidity Loss Considered?

I've been looking into Heat/Energy Recovery Ventilation and comparing specifications of different models. As we know, HRVs transfer heat and ERVs transfer both heat and humidity to incoming air from outgoing air in cold/dry conditions, and do the reverse in hot/humid conditions.

I was looking at the specs and I couldn't really figure out how the latent recovery of an ERV was being accounted for when compared to the efficiency of an HRV. Perhaps the specs indicate this and I'm just not getting it?

In Mechanicals | Asked By Lance Peters | Mar 15 17
4 Answers

With a drainage membrane on exterior of foundation walls, is backfilling with gravel still recommended?

We're in an area where gravel runs pretty high in cost (monopoly effect.) On the exterior of our basement walls we'll have sprayed in place Tremco Tuff'n'dry H8, with Tremco Warm'n'dri drainage board installed prior to back filling. So is it still a no brainer to backfill with gravel or might we be able to skip this and save some cash? We haven't excavated yet, but soil in this area is classified as "silt loam" - in other words it's not a heavy clay, but it's not light, sandy soil either.

In Green building techniques | Asked By William Costello | Mar 19 17
8 Answers

Where should I apply polyiso in an attic? South wall?

My budget is $2000. Built in 2002. I have average R40 attic insulation a combination of blown pink and rolled pink. My thought is to add R10 poly iso to the attic but I wondered the best way to do it. R10 would be from two layers of 3/4" R5. The attic is large and ventilated with 2x6" joists 24 OC. I has an existing radiant barrier that looks to be properly installed on the underside of the top of the attic I live in 3A W/H Dallas TX.

My first and best solution was to

In Energy efficiency and durability | Asked By user-6799229 | Mar 19 17
6 Answers

Maximum CFM for range hood without makeup air

In a tightly sealed house, what's the maximum CFM that you could consider in a range hood without supplying makeup air. I know that the IRC allows up to 400cfm without makeup air, but is that actually advisable? Any personal experiences about 200-400cfm fans in tightly sealed houses?

I'm considering putting in a fan that goes up to 350cfm, and opening a window if I need to run it at full speed.

-John

In Mechanicals | Asked By John Ranson | Mar 18 17
11 Answers

Electric vs. Propane Direct Vent Water Heater

Hi All,

My water heater is nearing the end of its lifespan and I am trying to decide the best option for replacement. My main criteria is lowest energy cost. Secondary criteria are installation cost and overall efficiency/greenhouse gas emissions.

Right now, I am limiting my search to storage units (no on-demand).

The unit I have right now is a direct vent propane heater. I pay about $4/gallon for propane (well over 4X the wholesale price ! Don't get me started about the unjust economics of residential propane). My electric rate is about $0.20/kWH.

In Mechanicals | Asked By Pierre Donner | Mar 18 17
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