The Power of Choice

Don’t you think that you should decide what fuel or power source heats your home? It is not an issue with air conditioning because electricity powers the compressor that pumps the refrigerant through the coils.  This same compression system also works in heat pumps to gather heat from the outside air and release it to the inside air.

Heat-pump-cooling-heating-reversing-valve 2

A heat pump saves you money by working in both directions.

Your choice for heat is influenced by history. Central heat or forced air furnaces were already in common use when air conditioning began to gain popularity.  It was easy for pioneering contractors to install an outside unit and pipe the refrigerant to an inside coil that they placed in the forced air stream.  Heat pumps were theoretical and complicated in those days.  I live in the Tennessee Valley and hydroelectric should have made a serious challenge to promote heat pumps.  Fossil fuel is still very prominent and heat pumps are used when natural gas is not available although there are exceptions.  In the modern era, heat pumping is a mature technology. Recent advances have led me to make the bold statement that with few exceptions, all air conditioners should be heat pumps.  When gas is available, it should be used as back-up for the heat pump.

Without even considering a heat pump. It may have been that the person who made the decision believed the negative publicity about heat pumps that has been perpetuated by “BIG OIL”. The fact is that modern people walk in and out of buildings all day that have either heat pumps or furnaces and don’t know the difference. Please allow me to shed some light on the subject. It’s not too late to improve upon the decision that was made. There is a new technique that dramatically improves existing air conditioning equipment. It pays for itself in the form of utility savings, increased comfort, and tremendous improvements from the perspective of conservation. Cars used to only get 10 miles to the gallon but gas only cost 26 cents per gallon and people weren’t concerned about air pollution. Hybrid cars have improved that equation dramatically but no one has engineered a hybrid upgrade for existing automobiles. That is precisely what I have done that for all air conditioners that are not heat pumps. That is why I am writing this and I hope that you appreciate that I have revealed my agenda. My perspective is unique and it is not for me to make money. It is to improve the HVAC industry by highlighting heat pumps and to encourage building owners and decision makers to upgrade their existing equipment. It will help you to know that you have a choice by learning that all air conditioners are not created equal.

Air source heat pumps are called that in order to differentiate them from ground source or geothermal heat pumps. Ground source units use the temperature difference in the ground to absorb or release heat most efficiently. Air source are more common, partly because they are much less expensive to install and it is therefore much easier to recover the installation or change out expense. This return on investment or ROI, comes gradually in the form of savings on utility bills. If you have the money, it is an investment to buy more expensive equipment that is less expensive to operate.

Air source heat pumps and straight air conditioners can be mounted on the roof or alongside a building and can be packaged either complete or as split systems. Fossil fuel burning systems need a refrigerant compression system for air conditioning, but heat pumps can provide heat by itself. The system that is used for providing heat for furnaces can be upgraded into a heat pump. I , David Evatt am the inventor. I didn’t invent the heat pump. I pioneered and perfected the process of upgrading an existing air conditioner into a heat pump.

In cooling mode, the unit operates like a typical, or straight, air conditioner by releasing the heat gathered from the building into the outside air. In heating mode, the same system used for cooling operates in reverse, extracting heat from the ‘outside’ air and using it to provide space heating by releasing the heat into the ‘inside’ air. Air-source heat pump systems range in size from about 1.5 to 25 tons. High-efficiency air-source heat pumps have an EER as high as 11.5 and a COP for heating as high as 3.6. This coefficient of performance, or COP is what makes a heat pump so attractive. At idea conditions a heat pump can take 1 unit of electricity and derive 3.6 units of heat from the outside air.


These units for measuring heat are perfectly environmentally friendly even if the electricity is not generated ideally. The most harmful method of electricity generation (environmentally speaking) is burning fossil fuels and even then, the 3.6 units of “free” heat make it more attractive to use them to power a pump heat than to make heat by direct burning or resistant heating. Perhaps another COP could be used in an illustration called coefficient of pollution. Burning fossil fuels is never preferable but can be considered forgivable when it is very cold. More forgivable when you have pulled as much free heat from the outside air as you can. This can only be done with a heat pump. How nice it is to wring out the dishtowel and feel the big brother take over right when it starts to get cooler than your comfort level. In this way you never feel the cold air that has given heat pumps a black eye by the negative advertising campaigns portrayed by the fossil fuel providers. That cold air comes from running heat pumps in low ambient conditions. The outdoor thermostat on a hybrid heat pump system allows the heat pump to cut off before it would try to gather heat when it is just not there.gas heat

We don’t want to talk bad about natural gas because we need to make a compromise with it. The fact is that sometimes it is just too hot.

Air-source heat pumps have always been able to offer an attractive alternative to straight air conditioning units in cases when one needs to be replaced or a new unit is needed. Now you don’t have to wait until your system crashes.

Finally there is an opportunity to upgrade a straight air conditioning unit to take advantage of heat pumping ability when conditions are favorable. Compared to

  • straight air conditioners that incorporate electric resistance heating coils, heat pumps offer improved year-round energy efficiency and…..wallet
  • compared to straight air conditioners that incorporate gas heating, heat pumps can offer cheaper operation where gas prices are high and electric rates are low. That is why a cooperation is in order. Heat pumps when the weather is mild and burning fossil fuels when the ambient temperature is below freezing. The environment and your pocket book are both recipients.

    Even when economic conditions are not ideally favorable for heat pumps, it is always more environmentally favorable. To utilize hybrid technology for the ability to pump heat when the outdoor temperature is favorable is the most attractive heating option both economically and environmentally. It is also more attractive to upgrade an existing straight air conditioning system into a hybrid for the benefit of the ecosystem and to save money on utility bills.

    • Even though heat pumps are best suited to relatively warm climates, such as the south- eastern U.S; a hybrid heat pump from the factory, or a system that was straight air and has been upgraded to hybrid can, extend the range further north. It can do this because :
    • the northern climate still has a lot of mild weather for heat pumping and back-up with fossil fuel or other.
    • When the outdoor temperature falls to below freezing, it causes the thermostat to automatically shut-off the heat pump and bring on the other. This is because when temperatures are low, a heat pump’s COP falls dramatically: A 7.5-ton rooftop heat pump that has a high-temperature COP of 3.0 can have a low-temperature COP of 2.0 or lower. And at very low temperatures, a typical or non-hybrid heat pump can require supplemental heat, this would typically be in the form of electric resistance so effective heating efficiencies become even lower. Hybrids use the back-up heat alternatively rather than supple-mentally. That is why dual-fuel, or hybrid heat pumps are best. In areas where natural gas is not easily available, LP or liquid propane can be used as the back-up heating source. p>

    This information is from the Environmental Protection Agency Building Upgrade Manual. It has been modified so that homeowners can understand the benefits of Upgrading existing straight air conditioners into hybrid heat pumps. For a free determination of the potential of your air conditioner, fill in the contact form. Hybrid Upgrade must be performed by professionals so if you have a service company who takes care of your equipment, please nominate them as a preferred installer. They will be briefed and dispatched to help you help us to help the environment. The estimated net savings on your utility bill is between 30 to 40 %.(Depending on the price of utilities in your area.) The time for ROI (return on Investment) is between 2 and three years. The cooling mode will be more efficient as well. The saving time is open ended because once a homeowner sees the benefits, the home will always have a heat pump. The electric utility benefits also because in the heating mode, peak season demand is offset by the back-up heat. Homes with zoning are even better candidates because a smaller heating zone can be heated at lower outdoor temperatures. Less heat is required to heat only the bedrooms at night. Ecovent currently authorized to use the Hybrid Upgrade in its marketing campaign.

    The benefits to the environment for dual fuel heat pumps……priceless.



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