Green Building Two

I have had two clients recently, two in the last 10 years to ask for Green or Energy Efficient qualities incorporated into their home design. This started me thinking about when I became involved in GreenBuilding. A builder that I worked for started me on this path in 1998 when this movement was in its infancy in Virginia. We had a client who worked for Virginia Power who was looking for Energy Efficient design that Virginia Power was pushing. At the time Virginia Power was looking for ways to increase the use of heat pumps and therefore power but underneath that they were creating better more sustainable homes. From my involvement then and through continued involvement over the past decade I have come to believe that there are a few simple things that can be done to provide superior energy efficiency that will pay for itself in a limited time frame:

1. CONDITIONED CRAWL SPACE – Conditioning the crawl space does several things that are beneficial to the home. Moisture control is probably the top item. Homes are starting to be built tighter but controlling moisture is not generally considered in the building code or by the builder. As humans we create and transport quite a lot of latent moisture into our homes. We need to be able to control this and having a conditioned crawl helps in that the moisture from external sources has one less path to enter the home.

2. BUILDING ENVELOPE – The crawl space is a part of this but equally important is how the walls perform. There are methods to create a wall of windows that is more energy efficient that a solid wall but very few of us live in glass houses. Air-sealing the building envelop thru the use of caulks, foams, and/or blown in batt (cellulose) or icynene (expanding foam) insulation will help to stop air infiltration thru the thousand of cracks that are in the framing. Building wraps, such as Tyvek, do much the same thing but should be viewed as a supplement to these other suggestions not as the cure. The building code now requires a building wrap to be placed under the exterior cladding and in my area 15# tar paper is just as effective as the Tyvek or other high end building wrap. The environment in my locality does not support the literature for the use of high end building wraps because we do not get too warm or too cold for too long.

Thanks for reading and I look forward to hearing from you…

Posted in Energy Efficiency, News, Residential.

One Comment

  1. Great post Charlie! My wife and I used several “green building techniques” in our recently completed addition. I focused on the greatest return for the “green” investment (ROI). After a ton of research, we went with several upgrades beyond code:

    – Structural Insulated Panels (SIPs) for the walls (not more expensive as some GC folks will tell you due to savings such as significantly less labor, waste, etc.),
    – conditioned crawl space (a must if you “must” have a crawl space – 2″ Thermax on exterior walls, allows you to run HVAC ducts under the home in conditioned space, etc.),
    – increased the “heal height” on the roof trusses by a foot (allows more attic insulation where you need it at the pinch point where the roof meets the walls),
    – “rain screen” for the exterior walls under the siding (smart building science and I believe it might be code a decade from now – already is in some jurisdictions),
    – Hybrid heat pump water heater located in the home – mudroom (60% less energy use and it cools the inside of the home during summer months – cool, dry, exhaust from the heat pump – the water heater is now an air conditioner too),
    – upgraded HVAC system inside the building envelop (moved from unconditioned attic to utility room inside – most of the ducts are now within conditioned space),
    – second floor joists “hung inside the building envelop” (joists don’t contact the outside at all – no need to try and fill every void at the end of the joists – more energy efficient and stronger building design according to engineering data), and
    – a bunch of other small details (extra attic insulation – R50, foam/caulk every little crack, etc.).

    How did we do? Our electric bill for January 2014 was LESS than our January 2013 electric bill after adding about 1,600 sq. ft. – I was amazed given it was a really cold January this year.

    I have a blog that discusses some of the techniques and I’ll keep you posted as I have time to publish everything. Let me know if I can use your post as a guest post on the blog: – thx.

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