Free Hot Water From

Airconditioning and Refrigeration

Waste heat

Written By Scott Meenen
From G&S Mechanical Services of Maryland.
Serving Baltimore and Washington
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If you have central Air-conditioning or a Heat pump system that you feel uses too much electricity and which you have considered replacing to gain energy savings, then consider an alternative.

A new air conditioning or heat pump system costs about $2500 to $3000 or more and will take many years to pay for itself. Instead of replacing your perfectly good working, but not so efficient unit, consider adding a Hot Water Recovery Unit by Trevor-Martin, the same people who make Trion electronic air cleaners and now hermidifier home humidifiers. If you have electric hot water you can be spending 50% or more of your electric bill each month to heat water. We can eliminate this by recapturing heat that is normally discarded outside, and using it to provide free hot water, thereby removing the cost of hot water from your electric or gas bill in summer. A hot water recovery unit added to your central A/C unit can almost offset the cost of running the air conditioning.

If you have a heat pump unit then the savings are even greater. A heat-pump unit typically uses 1/3 (33%) the electricity to make heat as straight electric heat. Of course, an electric water heater uses 100% electricity to make heat.

If connected to a heat-pump whenever the unit is running, hot water is being made at a reduced rate. This occurs at any time, not just in the summer.

Other benefits: In both air-conditioning mode and heat-pump mode, the compressor will use less electricity and have a longer life. In addition, in air-conditioning mode, the unit will also cool your home better.

Investments: You will invest about $300 for the recovery unit. If you want the best system, you will invest another $200. for a second water heater, which is a standard 50 gallon water heater where the electric elements are not used. (In some cases this is not needed for operation, but it is recommended for maximum efficiency.) The investment for labor to install can be $250 to $400. Situations where the existing water heater is located on the opposite side of the house from the air conditioner or heat pump, having to run pipes through finished walls, or going through ceilings, requires more labor.

Commercial establishments can also benefit by using this heat recovery unit. This Trevor-Martin heat recovery unit can also reclaim energy from restaurant and food service ice machines, refrigerators, and freezers. The waste heat can help offset hot water costs especially for washing dishes since increases in refrigeration and ice making usually precede cleaning demands.

While most energy devices consume energy, this device actually saves energy that would normally be wasted.

If you currently have a gas fired hot water heater, due to the current cheap cost of natural gas, or oil the dollar value of your savings during the 6 month warm season will be less.

Yearly savings if your Cost of Electricity per kilowatt hour is:
 Family Size  $ .08    $ .10    $ .12   $ .14    $ .16
 3  $192.22  $240.27 $288.33  $336.38    $384.43
 4 $256.31 $320.38  $384.46  $448.54   $512.62
 5 $320.33  $400.41  $480.49    $560.67    $640.65
 6 $384.35 $480.43  $576.52   $672.60   $768.69
Savings estimates provided by Barry J. Segal of Segal Solar Systems.

This text written by: Scott Meenen * G & S Mechanical Return to the Home Page.