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42 Answers

Seeking an air-to-water heat pump

I'm looking for an air-to-water heat pump and feedback from those who've used them. We have a LEED for Homes project in Victoria, BC, perfect climate for heat pump, affordability of project prohibits groundsource for 36Kbtu heat loss of 1800 ft2 home and for optimal comfort, low temp/efficiency, to avoid ducting we're selected hydronic in-slab for heating distribution thus standard air-to-air heat pump is a no-go.

In Mechanicals | Asked By Allison Ashcroft | Jul 28 09
5 Answers

Sub slab insulation with Superior Walls

Does anyone have a solution for how to insulate below a basement slab when using Superior Walls for a basement? The closest thing I could find was this link here:


I'm not exactly sure how they dealt with the edge near the walls. Is the gravel base graded at different levels to accommodate the different levels of foam?

Is the loss of R value in the floor near the wall a big enough deal to worry about?

In Energy efficiency and durability | Asked By Brian W | Sep 29 15
4 Answers

Insulating a workshop roof

Hey all,

I'm in the process of rebuilding a back-yard workshop in climate zone 3, and I'm at the point where I'm considering roof insulation. I've read many of the articles on here by Martin and others, including:
- How to build an insulated cathedral ceiling
- Cut and cobble
- http://www.energyvanguard.com/blog-building-science-HERS-BPI/bid/72240/D...
- http://www.greenbuildingadvisor.com/community/forum/general-questions/42...

In Green building techniques | Asked By Jon M | Jan 25 16
11 Answers

Heat-pump water heater in Canada?

I live in Nova Scotia in zone 6B. We're thinking of installing a heat pump hot water heater (my husband would do it himself) and not sure of how efficient it would be. We just bought the house, and the inspector told us (he used an infrared camera) that the house is well insulated. It was a Kent Home built in 1986; a split entry. We are going to have someone install a mini-split ductless heat pump in the living room upstairs. The rest of the house is heated by baseboard heaters. We pay 14.8 cents per kwh (no time of day billing).

In Energy efficiency and durability | Asked By Sarah Poulin | Jan 25 16
13 Answers

Heat pump sizing

So I have a completed manual J.

96k heating load, 47k cooling load. Big house renovation.

Am heavily exploring minisplit options for whole house... but could someone generally share with me how sizing would happen for a tradional ducted heat pump?

I will do a manual s and d, but would like to have a bit of direction on which way I am going to go before I choose.

So generally, how do you choose the sizing of the units? Do you size for the cooling load? The heating load? or somewhere in between?

Thank you!

In General questions | Asked By dean sandbo | Jan 23 16
1 Answer

Addition: Roofing options

I am planning on adding a sizable addition to my home and realize one of the areas that has the least insulation is where the trusses meet the wall.

Unfortunately my original home does not have raised heal trusses so I don't think I can add that now. Also, after looking in the soffits some of my rafter bays are completely full of cellulose or stuffed with Fiberglass batts. I have not made it far enough into the cathedral attic to see if I have moisture issues at this time.

In Energy efficiency and durability | Asked By Mike M | Jan 25 16
5 Answers

Carrier Greenspeed: real world performance?

As my propane furnace celebrates its 22nd birthday, I am plotting its destruction - err, replacement. I've been modeling various alternatives (mini splits, GSHP, even solar thermal "thermal battery"), and I've run into a problem - the Carrier Greenspeed absolutely dominates thanks to the, uh, "optimistic" information on their engineering data sheets.

In General questions | Asked By Tim C | Jan 22 16
2 Answers

Drainboard or XPS on basement walls? (Tying to existing drainboard)

I am finishing a 1400 sq/ft basement on a remodel for a home built in 1948. Poured concrete foundation walls on beefy footers with a poured concrete slab (no insulation or vapor barrier under the slab).

The foundation walls are in excellent shape with just a few/thin cracks. There is no water intrusion on the walls. We just had one of the worst months of total rain fall. The walls are dry. All good.

In General questions | Asked By Eric Schmidt | Jan 25 16
11 Answers

Are ground-source heat pump systems a good choice for beachfront NW Florida new construction? A cost-effective choice?

I haven't seen articles explicitly describing GSHP builds in sandy beach environments in temperature zones such as Panama City Beach area. Assuming a goal of a Passive House or net-zero with PV on roof, is it economical or not advised.

In Mechanicals | Asked By Jim Sutton | Jan 25 16
3 Answers

Stump the Geeks — Window angled in: what's it called?

Here are two examples: What is the right architectural terminology for them?

Example #1 Description: A pair of windows in the corner of each the rooms

Example #2 Description: A grand window projected inwards (Example in Strawberry Bank Portsmouth NH) I think it was a candle shop storefront.

In General questions | Asked By Hallie Bowie | Jan 25 16
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