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Dr. Energy Saver was called to replace an old, inefficient oil furnace in a 70 year old house with a high efficiency heat pump system and a propane gas furnace backup.
Let's take a look at this new HVAC system that we just installed; the air conditioning system moves heat from the inside to the outside so there's a coil or radiator looking thing inside the duct work and one on the outside that moves the heat.
With a high efficiency furnace we can get up to 96% efficiency which is exactly what we have here on the propane furnace backup side but with the heat pump we can now get up to 300% efficiency because we're not creating heat. Since we are moving the heat from the outside in we now have these very high efficiencies and it makes more sense economically to run the high efficiency heat pump especially in this climate than it does to run a regular furnace.
With this house being 70 years old and having never seen air conditioning this homeowner is going to be very happy. One of the features of high efficiency equipment would be a condenser that you can see is much larger compared to the little squatty ones we have all seen outside of homes and they aren't very efficient.
However if we need a full shot, 100% full power both compressors will run and get us the results we are looking for. The idea is that the high efficiency system will use as little energy as possible to get us what we need and since we only pay for electricity when it's running through the meter or when gas or oil is running through the heating system, the lower your cost of homeownership, heating and cooling bills will be.
Read Full Transcript:
Hi, I'm Larry Janesky from Dr. Energy Saver, today we are looking at a house that is an original Sears & Roebuck home that is over 70 years old and has an old oil furnace that is very inefficient. We changed the old oil furnace to a high efficiency heat pump with a high efficiency propane furnace backup and a high efficiency air conditioner. Let's take a look at this new HVAC system that we just installed; the air conditioning system moves heat from the inside to the outside so there's a coil or radiator looking thing inside the duct work and one on the outside that moves the heat. The heat pump works the opposite way; it moves the heat from the outside to the inside. Here in the northern climate some might think, "Gee, there isn't much heat in the outdoor area, say 40 or 45" when in actuality there is enough heat for us to move from outside to inside. With a high efficiency furnace we can get up to 96% efficiency which is exactly what we have here on the propane furnace backup side but with the heat pump we can now get up to 300% efficiency because we're not creating heat. Since we are moving the heat from the outside in we now have these very high efficiencies and it makes more sense economically to run the high efficiency heat pump especially in this climate than it does to run a regular furnace. Now if the temperature drops, in this case 35˚, the high efficiency propane backup will start to run and the heat pump will stop running since the propane is more efficient to run. If we take a look inside you will see a coil which is the heat pump coil and the evaporator coil or cold coil for when the air conditioner runs in the summer.
Down here we have a variable speed blower which is very important to high efficiency equipment since it can't run from 0-100% all at once. So if you only need a little heat it will run slower and will speed up if the need for heat increases. For example when the blower shuts off the action of the blower running, then when the burner shuts off it will push all the remaining heat out of the ducts into the rooms that you're trying to heat instead of trapping the heat in the ductwork. Additionally we have a 2-stage gas valve that will partly open so we have a little bit of flame in the furnace and the blower will be running on a slower speed. When we need a lot of heat the gas valve will open fully and the blower will ramp up faster so we can get a lot of heat into the home and that will save on energy. There's also a PVC intake pipe that goes directly to the outside so when this furnace is running its not drawing combustion air from inside the basement. Most furnaces, boilers, water heaters and other gas and oil equipment do suck in the air from the basement or room they are located in for combustion then blow it out the chimney.
Now new air needs to come into the home to replace the air that went out the chimney and essentially all we did was create a vacuum in the basement. If your asking yourself where does this air come from? Well it's coming from the outside through any leak it can get through in the building assembly and when outside air comes in during the winter its cold, then in the summer it's hot and humid which we really don't want because then we have to heat, cool and dehumidify the air for it to be comfortable. The propane furnace is so efficient at squeezing the heat out of combustion gases that 96% of that heat is getting to the house and only 4% of the heat is going out the chimney. Exhaust gases are so cool now that we are able to run them through the PVC pipe; can you imagine that, the PVC pipe now will act as your chimney going out the side wall of the home. Another advantage is that we don't have any drafts when the equipment is off like you would with a traditional chimney. Also we now have a dedicated air intake with dedicated air outside and we're not connected to the indoor environment making it much safer and more energy efficient. Another one of the features of high efficiency equipment is a draft inducer which is a fan that draws the hot combustion gases downward which is one of the ways that they can squeeze all the heat out of the combustion gases. Since heat rises we're now forcing that exhaust gas downward through the heat exchanger while getting all the heat out of the combustion gas and then blow it outside.
With this house being 70 years old and having never seen air conditioning this homeowner is going to be very happy. One of the features of high efficiency equipment would be a condenser that you can see is much larger compared to the little squatty ones we have all seen outside of homes and they aren't very efficient. On this new one there's a lot of surface area there the air can gather heat or release heat to the outside, so this unit has a seasonal energy efficiency ratio which is how these systems are measured. So if you have an air conditioning unit that's 12 years old your seasonal energy efficiency ratio is a SEER rating which might be 10 or 8 if its not maintained causing it to have a poor charge and it's dirty since it hasn't been cleaned out. This is now going to get these homeowners a lot more cool air or warm air because it's a heat pump as well which uses a lot less electricity. With the two compressors on the inside it makes it a 2-stage unit, so if we need only a little cool air when the air conditioner is running only one compressor will run. However if we need a full shot, 100% full power both compressors will run and get us the results we are looking for. The idea is that the high efficiency system will use as little energy as possible to get us what we need and since we only pay for electricity when it's running through the meter or when gas or oil is running through the heating system, the lower your cost of homeownership, heating and cooling bills will be.
If you have an old heating and air conditioning system that you would like to upgrade to high efficiency equipment call Dr. Energy Saver. We will evaluate your home while looking at the whole house as a system; identify the priorities since the first priority may not be to replace your heating and air conditioning system, maybe its air sealing and insulation or repairing the ductwork. So what we want to do is lower the heating and cooling load in your house before we replace the system because if we could lower the load when we do replace the system not only will we be putting in high efficiency equipment in but we can make smaller equipment so you get the best of both worlds. So call Dr. Energy Saver, we can help you!
