Heating with Heat Pumps | HVAC Systems - There are some people who say that heat pump heat is not as warm as other types of heat. Heating sources such as a hot water boiler or even a steam boiler. Even the forced air gas furnace gets more credit for providing better heat than the heat pump. Heat pumps are extremely popular in the southern states where the heating season is short. Additionally, where the temperature rarely dips below 35 degrees F.
Heating with Heat Pumps
The heat pumps in the southern states usually utilize electric heating strips. Those are for those rare times the heat pump cannot keep up. It is in those unusual times when the temperature in the south dips below 35 to 40 degrees. Some of the more expensive units use a secondary heat of gas in the form of a gas furnace. Whatever people say we will attempt to dispel this myth that heat pump heat is not as good as other types of heat.
Heating with Heat Pumps - Heat Pump Myth Possible
If we know the sequence of operation for a gas furnace we understand that the burners on the gas furnace kick on and begin heating the heat exchanger a minute or so before the blower motor kicks on to blow the air through the ductwork. By delaying the blower motor and allowing the heat exchanger to heat up the blower can deliver warm air sooner than if the blower came on at the same time the burners turn on.
With most heat pumps the blower turns on right away. If the air in the ducts is 50 degrees Fahrenheit then it will feel like the heat pump is blowing 50 degrees Fahrenheit air. We will definitely feel cold. So it is possible for one to think the heat pump doesn’t deliver hot air all the time when the blower kicks on and purges the ducts of cold air.
Another reason is the temperature coming out of the supply vents. This temperature can be 90 to 95 degrees F. That temperature is cooler than the human body temperature. Even though the heat is providing heat the temperature is still below human body temperature.
Why not delay the blower for a short delay and allow the refrigeration part of the heat pump time enough to generate the heat enough so there will be minimal cool air blowing from the ducts? Of course, as I am writing this someone or some manufacturer has already made this change.
Heating with Heat Pumps - Heat Pump Sequence of Operation
Before making changes to the sequence of operation for a heat pump we must first analyze how a heat pump works. Put in simple terms, it works in reverse from how the air conditioner cycle works. Except when the same heat pump is in the cooling mode.
The reversing valve facilitates the heating and cooling cycle by reversing the process. It makes the condenser a condenser and an evaporator in cooling mode. In the heating mode, the evaporator becomes the condenser and the condenser becomes the evaporator.
In the heating mode, the heat pump condenser is used as an evaporator and absorbs heat from the outside air. This heat is transferred inside where it is used to heat the home.
Air Source Heat Pump Tips | Dual Fuel Heating
A dual fuel heat pump is a heat pump with a gas furnace for backup heating rather than electric heat strips.
Air source heat pumps have a backup heating source. In most installations, the backup heating source is electric heat strips. Electric heat strips are very cheap to install in most cases. However, while electricity is generally regarded as 100% efficient, producing it is more costly than other heating methods. For a more efficient heat pump, consider a dual fuel heat pump, or a heat pump with a gas furnace for the backup heat source. It will be more costly to install, but your monthly bills will be reduced.
Operating Sequence for Blower
So if we delayed the blower from turning on to allow heat to build up in the condenser (evaporator) then will we harm any other components? The hot gases coming from the evaporator are channeled back to the compressor via the accumulator.
It is possible the hot gases could harm the compressor. All of this could be engineered so no damage would be caused to the compressor. So if the engineering was done we could delay the blower fan probably 30 seconds and then we would experience the same air delivery temperature that we would experience with a gas furnace. Problem solved.
Heating with Heat Pumps - The Last Word About Heat Pump Heat
One other word of note about boiler heating systems. It is an opinion but I believe the best possible heat one can have is radiant heat. The type provided by a hot water boiler. The floor has tubing under it where the water runs through the tubing. This type of heat is even and comfortable. Especially when you walk on the floor and your toes are toasty.
In some cases, this type of heat is not available. That is because the home was built without taking this type of heat into consideration. Therefore, without major renovation and expense installing this type of heat is impractical. There are millions of people staying warm with heat pumps this winter and everyone stays warm all winter!
Heat Pump Heat - Heating with Heat Pumps