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1 Answer

Calculating Annual heating losses

I'm trying to determine cost effectiveness and payback periods for going with thicker insulation on the house I am planning. My project manager does not offer services of energy modeling, so I would like to do some of it myself. I will probably end up paying an architect for it, but I'd like to give it a go myself.

I calculated U-values for several walls, floors, roofs and windows. I have areas. I have heating degree hour value for my climate, which is ~78 000 (typical central europe). i have insulation prices.

It's extremely straightforward.

Asked By davor radman | May 24 17
15 Answers

How to deal with duct-work that installed in unconditioned attic and a powered attic ventilator?

I am a homeowner of a brick ranch built in 60s in climate zone 7 and it is about 1,800 sqft.

The previous owner had the furnace and ductwork were installed in the attic and a powered attic ventilator (PAV) too in 2013. The attic floor does have some fiberglass as insulation material and it is about 8 inches. The ductwork is insulated flexible duct (supply duct is black from the outside and the return duct is silver from the outside).

Asked By TedLiu | May 22 17
2 Answers

Heat loss calculation for a ductless system

I did a thorough whole house heat loss calculation for my project when I was considering doing radiant floor heat but I have now decided to go with a Ductless Mini Split system. On one of the final tables of my spreadsheet (where I calculate design day requirements), I seem to have put in a "Boiler Efficiency" factor most likely for the heat source for the water for the hydronics. When it comes to sizing the outdoor units, should I leave that final adjustment? I attached a picture of the table showing the data.

Asked By John Brown | May 24 17
2 Answers

Dense packing cellulose with the Krendl 425

Hi All,

I am going to attempt to dense pack several horizontal stud bays (2x10 floor joists, 12in o.c., between attached garage and bonus room) using the Krendl 425 (14amp 2-stage blower, pushing 1100 – 1400 lbs of cellulose per hour) over the upcoming weekend.

Asked By Joe Duchek | May 23 17
4 Answers

Average lighting, appliance and plug loads for PV sizing?

In doing some energy modelling for a future single-family net zero residence (in Canada), I am running into the problem of trying to guesstimate what the total lighting, appliance and plug loads will be. Because it can be different with every specific family, I'm wondering if anybody has any links or resources they can provide that offer average values for these loads that one can use. I will calculate the heating, cooling and hot water loads separately, but am hoping somebody has some suggestions for those remainders.

Asked By Burke Stoller | May 23 17
14 Answers

Opinions on my exterior options

I have posted a few times regarding my situation and have been provided a lot of great information from GBA. I have not really been able to figure out what would be the best option for my situation. So i thought i would try and summarize and hope the minds here can point me in the right direction.

Current house climate zone 6
2x6 16"oc fiberglass batt
Wood siding
2.64 ACH

The siding is being ripped off as it is failing in multiple places

Inspect sheathing/framing for water issues, replace as needed
Tape seams of plywood
Add Tyvek or similar wrb

Asked By Jeremy Archer | May 15 17
20 Answers

Sealing PT sill plate to concrete slab ?

I am a homeowner in the midst of a 2000 sq ft addition. Houston TX, foundation is a concrete slab. Walls (from inside out) are drywall, stick 2*4 framing with open cell foam, OSB, tyvek, air gap, brick veneer.

The builder used pressure treated 2*4s for the sill plate but there is no (capillary) barrier between the concrete and the sill plate. 3.5" of open cell spray foam is going in the exterior walls today.

Asked By Mark McFarlane | May 20 17
2 Answers

Use foam board underneath fountain footer?

I am installing this fountain in PA:


I don't want to dig 36 inches to the frostline.

Can I dig 2 feet, put tamped 3/4 clean stone, place XPS foamboard and then pour concrete?

Asked By John Sean | May 22 17
4 Answers

Passive solar design and HVAC sizing

I just used CoolCalc.com software (free to use online) to do a Manual J. analysis of my heating and cooling needs, since I just found out that I may need to replace my 13 year old HVAC system. One of my 2 heat pumps has a leak and needs to be recharged, and I am considering my options, so I wanted to get an accurate estimate of my heating and cooling needs. I found that the Manual J. heat loss calculations do not take into account the heat gain from the passive solar design, (except for cooling loads).

Asked By Ron Nachman | May 22 17
7 Answers

Can I combine floor and wall heating in a solar passive house to avoid overheating?

I have consulted many "experts" on highly insulated houses, most of them recommend to use ductless heat pumps to heat the house. But I am a radiant heat addict...
Apparently the problem with radiant floor and passive solar is that when the sun comes out, the southern side of the house is too hot because the concrete slab has heated during the night and is warm and when the sun comes out it can bring it to a much higher temperature.

Asked By Micheline Freyssonnet | May 22 17
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