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

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6 Answers
Oil vs propane - Need help with calculation

Oil $138,690 btu/gal, $3.02 gal, Furnace 75" efficient
Propane 91,333 btu/gal, $2.75 gal, Furnace 95% efficient
Then
Cost per "delivered" btu is
Oil: (138,690 x.75)/$3.024 = 34,397 btu's delivered per dollar
Propane: (91,333x.95)/$2.75 = 31,154 btu's delivered per dollar

So how many gallons of propane equals 1 gallon of oil after allowing for system efficiency?
Calc 1:
31,154X=34,397
X=1.1
so you need 1.1 gallons of propane to equal 1 gallon oil, so
$2.75x1.1=3.03
Which is about equal to the current cost of a gallon of oil

or is Calc #2 the right one to use?

Calc 2:

In Mechanicals | Asked By Walter Gayeski | Jun 21 10
9 Answers
Sill gasket for airtight drywall approach?

I am building a double stud wall house in Canada and have just finished the dense pack cellulose behind netting and preparing for ADA. I would like to use a gasket at all necessary areas (top/bottom plate, windows, doors, etc) behind the drywall instead of acoustical sealant to least interrupt the drywall installation i.e. we would put up all necessary gaskets ourselves and then the drywallers would just install as usual. Probably have them add screws every 8 inches to ensure full compression of the gasket and sealing of the joint.

In Green building techniques | Asked By Brian Mahoney | Jun 28 10
5 Answers
ASHRAE 62.2 2010

I saw recently that ASHRAE had published an updated ventilation standard for residential ventilation (62.2 2010) that is supposed to make fulfilling the standard easier for existing home retrofits, only I can't find out what the changes are. Rather than buying the standard myself, I'm wondering if anyone can give me a quick summary.
Thanks.

In General questions | Asked By Amanda Evans | Jun 29 10
5 Answers
Crawlspace ventilation or not; what is best for insulation?

I am building a workshop. The foundation is being built on bedrock (8 inch stepped foundation concrete wall with PT wood kneewalls to bring it up to floor joist level). The granite bedrock is sloped and therefore has surface water draining from the higher ground when it rains. The perimeter of the foundation (29' x 20') will have gravel and weeping tile.

There will be moisture present on the granite surface, regardless of my drainage plans.

My questions are :
1. Do I vent the crawl space?
2. What is the best way to insulate the the floor?

In General questions | Asked By mike | Jun 26 10
15 Answers
When air-sealing a house, does it always make more economic sense to make the house as tight as possible and then add mechanical ventilation or to air-seal down to some building tightness limit?

I'm working for an energy efficiency retrofit program. We have a very limited budget for our houses and therefore have been air-sealing down to the Minimum Building Airflow Standard (ASHRAE 62-89) so that we don't have the extra cost of mechanical ventilation. Is this flawed thinking? Is it usually in the economic interest of the client to air-seal as much as possible and then have the extra cost of putting in a vent fan?

In Energy efficiency and durability | Asked By Karen Leu | Jun 8 10
3 Answers
Post and pier foundation

Can I use a post and pier foundation in Michigan?

In Building Code Questions | Asked By Gary | Jun 26 10
13 Answers
Ads at this site for non green items????????

Just posted on the blog to do with wood burning...

The ad that came up that pays for this site's existence was for an outdoor
wood burner... the one pictured sure doesn't look like a gasification unit
and if it is made to produce 200,000btus for a home that is poorly sealed and insulated,
then... I don't get it.

For what I calculate.... passive house living can be achieved for a nomal size home with as
little as 1KWH of e... 3400btus per hour.

Green?

$$$$$ in the USA.... and everywhere... $$$$ is green to most....
including a site about building green.

In General questions | Asked By ADKJAC UPSTATE NY | Jun 21 10
14 Answers
How to insulate my roof... no attic

Hi everyone,

I live in a house built in the 60s. It is a California Modern design (or so I'm told). It has very low roof pitch with 2 simple gable end roof sections. Inside it has exposed beam / vaulted ceilings. When you look up inside the house, you see 4 X 10 beams every 6 feet running as rafters would and then you see tongue and groove 2 X 6 roof decking running between the beams.

In Energy efficiency and durability | Asked By Bryan Wilber | Jul 1 09
18 Answers
Greenest Home?

http://money.cnn.com/video/fortune/2010/06/02/f_v_greenest_home.fortune

I would love to build this home.... but...

I thinks we need at least two definitions of green (along with whatever your favorite variable is)

1- cost to build matters that it is low
or...
2- cost to build matters and one should spend as much as one can for all the goodies.

In Green building techniques | Asked By ADKJAC UPSTATE NY | Jun 22 10
14 Answers
Cedar Shingles Directly Over Rigid

http://www.greenbuildingadvisor.com/community/forum/energy-efficiency-an...

Continuation of previous thread...It is difficult to resurrect an old thread....See above link for previous discussion.

Has anyone tried using typar w/ homeslicker (or the TYvek Drain Wrap product) over the rigid and attaching the shingles directly over the typar, fastened through the rigid back to the sheathing w/ 2.5" ring shank nails?

In Energy efficiency and durability | Asked By Chris Harris | Jun 23 10
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