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Tips to improve your HERS score

Thursday, September 22, 2016

by Steve Sutter

Tips to improve your HERS score - HVAC system design and advanced framing techniques

When using RemRate, if you can eliminate the default assigned value you will almost always improve your HERS score.

Pay attention to the design of the HVAC system

  • Check the Air Conditioning, Heating, and Refrigeration Institute (AHRI) Directory of Certified Product Performance web site to be certain the products specifications are as energy efficient as you can comfortably afford.
  • Searching the AHRI site can be difficult for the novice, but with perseverance this search site is unequaled, and highly respected in the industry.
  • In particular watch for the Auxiliary Electric Use or EAE of the furnace being specified.  This value is the energy used by the blower motor.  As usual the default value assigned in Rem can be much higher than the actual usage.  It’s also helpful to use as a comparison to other blower motor usages. 
  • Specify an Electronic Commutating Motor (ECM) if you can afford it – and you can afford it.  These DC motor are much more efficient than a regular AC motor.

Use Advanced Framing Technics Here I will digress for a minute:  The web site suggested above is one of my favorites and is my first go to site for all things Building Science related.  Joe Lstiburek is the Principal owner of the Building Science Corporation, and one of the foremost authorities on nearly every aspect of the Building Sciences.  If you don’t believe me just ask Joe.  He’s an excellent presenter and overall good guy.  If you get a chance to learn from Joe take it.  As I said though I digress.

Advanced framing techniques – whether side walls or raised heel trusses – reduces the occurrence of wood framing within the structure without compromising the integrity of the structure.  Less wood = more insulation = higher efficiency.

Measure the length of the supply and return ducts.  Eliminate the default values on the duct system page.

Make certain the appliance page is filled in accurately.  Buy/provide Energy Star appliances whenever possible.  Even the ceiling fan values can make a difference.  The washing machine values can change the HERS by up to 2 points from the default.