Tuesday, July 30, 2013

Finish Werks Tackles Energy Savings on a Budget

Yesterday I had a modular home builder email and ask what I thought was the most important part of energy conservation he could offer at a reasonable cost to her customers. Some of them were balking at the cost and she is trying to give her customers the best ROI.

So as I always do when it comes to all things “Energy” in modular construction, I asked Harris Woodward, Finish Werks Builders, in Savage, MD to help. He is known for his innovative contributions to modular housing when it comes to helping people save money on their energy costs. Here is his answer to the question and I think if every builder and new home buyer would adopt these simple procedures, it would reinforce why modular is the best way to build a new home.


The single most cost effective way to save on energy bills using modular constructions economies of scale (e.g. purchasing power), in most climate zones (particularly colder, like ours and North) is to increase insulation. Go from a 2x6 at 16OC to 2x6 at 24OC, make sure the FG batt insulation is high density R-21, then order a minimum ¾” foam board insulation on the outside over the OSB sheathing to reduce thermal bridging. When you spec DOW foam board insulation, you can eliminate the house wrap when the foam boards are properly taped at the joints. See?... it doesn’t have to cost a lot to improve insulation.

Next is air sealing – the factory needs to caulk and preferably liberally spray foam all exterior wall penetrations (top & bottom plates, j-boxes, wiring plumbing). Again: modular economies should keep costs down here.

Next is fenestration. Spend a few dollars, particularly on South-facing windows and patio doors, to upgrade to lower SHGC (solar heat gain coefficient) ratings. Plygem has a great upgraded glazing that costs not much more than their standard MW Classic Low-E window. This reduces cooling loads in summer. To reduce heating and cooling loads, make sure the glazing has a low U-factor (this is the insulation value of the window/door).

Finally is HVAC. Once the envelope is improved using the techniques above, spend more here. However, you may not have to spend more since by increase the total R-value of the envelope, you will have reduced the required HVAC sizing. We’ve been able to cut the total tonnage of our heat pumps by HALF once we got done improving the building enclosure.


Call it tough love, but, the reality they don’t want to hear is that the builder is too ignorant to explain the benefits:
  • Savings on energy bills - $5,000 in upgraded building performance is just $25.33/mo on a 30yr mortgage at 4.5%. I GUARANTEE YOU THE CLIENT WILL SAVE MORE THAN $25.33/MO ON HER ENERGY BILLS. This is what we call a “no brainer”.
  • Better comfort and indoor air quality (no cold spots, no moisture or mold problems)
  • Better quality and durability
How could be any simpler to sell insulation?

I firmly believe that the modular industry could establish itself as the better method of building if it only adopted these simple truths.

W. Harris Woodward
Finish Werks
Member, Master CGP

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