Q&A: A Forum for Green Building Experts and Beginners

[Click map to enlarge]

Please register for a free account or sign in to ask and answer green building questions.

The usual rules of courtesy apply:
1. Be nice.
2. If you can't be nice, be polite.
3. If you can't be nice or polite — well, please be brief.

To attach a photo or illustration:
Under the box labeled "More explanation," look for the words "File attachments."
Click that, and you should be able to attach a photo.

Thanks for joining the conversation!


1 Answer

Is there a reliable way of repairing a double pane window if the seal has broken?

I have light gray spots appearing on the inside of the outer pane of a double pane sash window. They don't look like drops of moisture. More like translucent round snowflakes. Each round spot is made up of concentric rings. Frankly, they look beautiful.

I moved to this condo three years ago. The windows are about 7 years old.

In Energy efficiency and durability | Asked By stuart brodsky | Oct 26 14
3 Answers

What effect does home mass have on the peak cooling load?

Dr. Bailes presents a graph for his "old and leaky" condo in his blog "How to tell if your air conditioner is oversized". It demonstrates that his outside design temperature is reached at about noon. It also showed that the hourly run times for his a/c unit remain at lower levels until 5-8 hours later (notably peaking during hours 7 & 8). Presumably his "old & leaky" condo is not super insulated nor air tight.

In GBA Pro help | Asked By Ted Cummings | Oct 25 14
1 Answer

Spammers have Returned

It looks like those darn spammers have broken the "Math Code" Firewall
and or they have Learned Martin's Schedule.
.....
actually ....it looks like the "math test" has been removed.

In General questions | Asked By John Brooks | Oct 26 14
3 Answers

Oil filled heaters

I own a bungalow house with an apt downstairs. I have tenants upstairs and downstairs. Appx 600 square feet On each level. The house is heated by forced air oil furnace. The problem is the heat comes on everywhere Through house and can't be operated separately by the tenants. I've advised everyone to turn down Thermostat if you're out for awhile to let the other tenant "control the heat".
If someone leaves the heat on and the other tenant finds it to hot, they have to hit the kill switch to turn furnace off.

In Energy efficiency and durability | Asked By Tim Young | Oct 25 14
3 Answers

ERV, HRV, Dehumidifier retro fit before finishing basement

Hi all, I'm new here. Please bear with me with lots of questions.

I live in Zone 4A, with humid summer (100+ F, at least 3-4 months AC time), cold winter (-10 -- 0 F, at least 3-4 months heating), and wet spring and fall. Our house was built about 10 years ago. It has 3 HVAC systems for 4000 sq. ft. and additional 2000+ sq. ft. unfinished basement. Two HVAC systems are located in basement while the third one located in a closet on 2nd floor.

In Mechanicals | Asked By Wendy D | Oct 25 14
1 Answer

Crawl space with dirt floor and spray foam

I have a crawl space that is covered by walls wood and parchment. Above it is the kitchen hence there are kitchen pipes there that never froze. My garden hose supply line has frozen a couple of times in the past. There is also force air duct work in there. I brought in a number of different insulators and there is no consistency.

In Energy efficiency and durability | Asked By Paul Staffieri | Oct 25 14
6 Answers

How do deviations in average winter temperature affect energy consumption?

Off the top of my head I would expect a five percent colder winter to cost five percent more for heating, all things being equal.

In Energy efficiency and durability | Asked By norm farwell | Oct 24 14
8 Answers

Calculating how much air needed to even out temps for minisplit

I'm building an 800sf 2 story house, R20 under slab, R40 walls, R60 roof, as airtight as possible, but likely just double pane windows (due to cost). 12% glazing, mostly on south side, w/ 4" slab on first floor. Using Marc Rosenbaum's heat loss spreadsheet, I get around 4000BTHU building load here in Portland Oregon at the 97% coldest day of 23F and a design temp of 70F, so a delta T of 47F.

In Mechanicals | Asked By Tom Frisch | Oct 23 14
6 Answers

Thermostats with radiant floor heating

I recently read an article comparing forced air and radiant heat energy use. The finding showed that the folk with radiant heat set their thermostats higher than for forced air. I hope that I am not being silly, but how can a thermostat on a wall respond to radiant heat? If one put a metal foil around the thermostat ,but let air flow occur, would the thermostat read a different number? I read in Mr Lyles masonry stove book that a cathedral that had radiant heating only had a 2 degree difference between the floor and ceiling (75 feet up).

In Mechanicals | Asked By Mike Legge | Oct 12 11
12 Answers

Flat roof insulation

I have built an extension to my house with flat roof, continuation of the existing house. The rafters are 16 in apart and there is 6 in left for the insulation under the sheeting. The plans are requiring R30 insulation and the building inspector requested hard foam Thermasheath- 3, 5 in thick, leaving 1 in for breathing. The drywall was not installed yet, when water from condensation came down all over the place. There are vents on both sides of the roof, in each bay under the insulation level, not allowing the hot air to escape.

In Energy efficiency and durability | Asked By Angela M | Nov 22 13
Register for a free account and join the conversation


Get a free account and join the conversation!
Become a GBA PRO!