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In areas not served by natural gas, homes are often heated by propane based systems.  Unfortunately, propane is notoriously expensive compared to natural gas.  During HVAC replacement, many homeowners will prefer an all electric based heat pump systems  To convert from propane to electric, the propane line is capped (if other appliances in the home will still use it, such as a stove, fireplace or water heater) and a 230/240 volt dedicated circuit and service disconnect must be run from the circuit breaker to the air handler.  Gas and propane furnaces run on 110/120 volt.  Air handlers need higher voltage for the back-up heat strips.

See your local qualified HVAC contractor for more details.  Stay warm this winter.

So does it?  The quick answer is “typically not.”  At the 14-16 SEER single stage compressor range, most systems are virtually identical.  Upwards of 75% of components from brand to brand are manufactured by a third party company, including the compressor, fan blower and other electronic components.  The only components unique to a brand are often the evaporator coil, condenser coil and jacket (outside casing).

At the higher end of the efficiency range (i.e.- 20+ SEER), brand does become more important as certain brands employ newly patented technology to attain said efficiency tiers.

The most important aspect in purchasing a new HVAC system is the contractor.  Let me repeat that… the most important aspect in purchasing a new HVAC system is the contractor.

Please contact your local qualified HVAC contractor for more specifics.  Cheers!

Humidity should ideally be kept between 40-50% year around to maximize comfort in a home.  However, in warmer climates during the summer, humidity can creep above 50%.  Similarly, during winter or in cooler climates, humidity can fall well below 40%.  This dry air can cause sinus issues, wood creaking and electric shocks.

HVAC equipment with two or more heating and cooling stages help combat this.  In the summer months an air conditioner compressor runs at slower speeds (or “stages”), this helps reduce humidity.  In the winter months, a furnace running at slower speeds helps keep humidity higher.

Contact your local qualified HVAC contractor for more details and enjoy the rest of your summer!

Welcome to this edition of HVAC Tips.  Today we are de-mystifying the plenum.  The plenum is essentially the hard duct box which resides on both the return and supply side of your air handler, in the case of a heat pump system, or furnace, in the case of a natural gas or liquid propane heating system.

The plenum is typically insulated or lined and the main parts of a home’s duct system are affixed to said plenums.  It is critical the ducts on the supply side are connected further from the source of air, to allow for proper static pressure build up.  On an up flow application, the return plenum may be eliminated in exchange for connecting return ducts directly into either side of the furnace.

Contact a license and qualified HVAC contractor on how to best design your duct system.

The new heating & air system you were quoted… did it come with an AHRI Certificate?  AHRI, which stands for “Air-Conditioning, Heating and Refrigeration Institution,” is an independent governing body which tests HVAC system matches and certifies SEER ratings.

What is a system match?

• In a gas fired heating system, this includes the outdoor condensing unit, the indoor evaporator coil and furnace (which contains the fan blower).
• In an all-electric heat pump system, this includes the outdoor condensing unit (sometimes referred to as the heat pump) and indoor air handler (which contains the fan blower and evaporator coil).

A SEER rating is the combination of those above components.  Do not be misled by brand nomenclature.  If the outdoor unit is a X-18, for example, this does not mean you have an 18 SEER system.  Usually, one matched configuration can attain 18 SEER, but not all configurations.  System tonnage/sizing can alter the ultimate efficiency rating.

Always, always, always ask for an AHRI Certificate for any system you are potentially investing in.

A frequent question arises in consulting a homeowner, which is “Do I need to replace my furnace as well?” The answer is often yes.

The minimum SEER, which stands for Seasonal Energy Efficiency Ratio, is now 14 for the Southeast United States. If the a/c is replaced, but not the furnace, only the minimum 14 SEER can be guaranteed. This is because you are matching two new components (the condensing unit and evaporator coil) with an older component (furnace or air handler), which contains the fan blower.

Replacing all three components allows the homeowner to upgrade total efficiency beyond that of 14 SEER. Higher end furnaces contain high-efficiency and/or variable speed fan blowers. These types of fans run in heating and cooling mode and help maintain lower humidity levels in the warm summer months.

Local for-profit electric providers can offer rebate incentives for upgrading HVAC systems. These usually apply when both the a/c and heating side of the system is replaced.

Lastly, if a homeowner is experiencing less-than-desired cooling, the air conditioner could be undersized. One must be wary in upsizing the a/c only, as the furnace fan blower could be undersized as well, and the increased capacity will be wasted.

In summary, several factors beyond simply the increased capital outlay should be considered in evaluating whether a full system changeout is the better approach.

If a home has a gas furnace and separate electric air conditioning system, one option available is an a/c + coil change out.  The “a/c” stands for condensing coil or outdoor unit.  The “coil” stands for evaporator coil which is usually affixed to the furnace.  These replacement options are more affordable than a full system change-out but come with a few caveats.

• Utility company rebates often do not apply.  Utility companies, in their infinite wisdom, require both the a/c and heating side of the system to be changed out.  This does make sense in that the furnace blower operates whether the thermostat is calling for heating or cooling.
• Guaranteed SEER efficiency is often 14.  As with the previous bullet, this replacement matches new coils with an older furnace and fan blower.  Often times, much of the higher efficiencies are wrung out of ECM or X-13 fan blowers.
• Changing out both the a/c and heating system simultaneously can save the homeowner up to $500 in labor costs.

A common misconception in the residential HVAC space is the larger the system, the better the result.    Unfortunately, oversized systems can result in “short cycling,” which can lead to humidity problems particularly in warmer climates.  Short cycling also burns through the life cycle of critical components including the compressor and contactor.  Conducting a thorough load calculation by a licensed professional ensures systems are properly matched to the needs required.  All else equal, a system should run for longer cycles rather than shorter cycles.