My heat pump installation
Our former vacation home, and now primary residence, needed some improvements in the
heating, ventilation, and air conditioning system ( HVAC ). I decided to
retrofit a heat pump. Our heating consisted of
baseboard electric and our wood stove. Our air conditioning was a 12000 BTU unit in
the kitchen which we tried to use for the whole 1500 square foot home. The baseboard
heat of course does not actually provide any ventilation and it is the most expensive heat
you can buy; it is well zoned though. We also wanted to heat our basement
efficiently. (Please see my article on heating
our basement.) Central air would be very desirable in that we spend quite a bit of
time in all the rooms in our home, including quite a bit of time in the basement. No
air is needed for the basement, but it definitely needs heat, and a lot of it, in the
winter. I also have Spring and Summer allergies, so I hope a central filtered
air system will help with these allergies. We have gotten rid of most of our carpets
and replaced them with 3/4" solid hickory wood floors. The floors are beautiful
and the dust reduction is tremendous. Carpeting is a tremendous source of dust and
dust mites, I'm glad we're rid of it. Of course this really is to big a job to do
yourself in a reasonable period of time. But even if you hire a contractor, a lot,
and I mean a lot of oversight is required if you want the job to turn out well and end up
with the system you truly desire. Please also note, if you're installing
central air, spend a little more and install a heat pump. It can save you
money even if you have gas heat now!
Heat pumps can be 400% efficient
We didn't end up with the most efficient unit, BUT, we did end up with probably the most durable and simple heat pump unit in the industry. It's still efficient. For example it has an intelligent defrost cycle. The heat pump compressor measures the temperature differential across the heat exchanger coils to determine when and how long to defrost. This used to just be a timed event. The most efficient units have dual compressors, this is just too complicated for me, (and frankly for the installers).
Please remember a heat pump actually removes heat from the outside air (or ground). The heat pump compressor may consume 1 kilowatt of electricity but generate 4 kilowatts of heat! 400% efficient, wow! Baseboard heat is (only) 100% efficient, you can see why a heat pump can be cheaper, way more expensive up front though. Baseboard is the ultimate in simple however. Please see my article on installing baseboard setback thermostats, they're great!
Heat pump misconceptions
30 degree balance point, ridiculous!
Our Trane XL14i "Climatuff" heat pump will maintain our home's temperature down to 6 degrees F on a windy day with no auxiliary heat. That's with a 73 degree setpoint. The average low temperature here in North East Pennsylvania is 20 F. Of course it can get to 15 below, but that's pretty rare. Our home could still have much better insulation; it's about R15 in the attic. The house does have 6 inch studs, due to baseboard heat. This helps with heat loss for sure. So much information you see on the web says a heat pump's no good in climates that go below 30 F in the winter, that's ridiculous! Here is an excellent article about heat pump balance points, the problem is again this article chooses a balance point of 32 degrees F! It's just not the case any more unless you have a very old or very poorly insulated home!
Choosing the contractor for a heat pump installation
In our area this is actually a difficult task. At first I was interested in a ground sourced heat pump. They typically can produce more comfort and heat your hot water too! I had called two contractors claiming to be in that industry. One never returned my calls, and another never showed up for an appointment at my home. The third contractor I talked to on the phone tried to talk me into an air sourced heat pump. Our previous home was heated with an air sourced heat pump and this contractor had some very good arguments regarding why we should choose air sourced. So for the first time we actually had a contractor make it to our home. He proposed an air sourced Trane XL-14i 3.5 ton heat pump. The claim was this unit will produce heat down to 10 degrees F, sufficient heat to maintain the house temperature.
Decision points
We had to choose between R22 and R410A refrigerant, which of course is more expensive. Our contractor insisted that R410A will give us a lower heat balance point and of course it is the "future" refrigerant. R22 will be phased out in the near future. Also we had to decide whether we wanted dehumidification and high efficiency dust removal and of course we wanted both. The other thing to remember this is a full reftrofit requiring complete installation of ductwork and returns. We had vague hopes the ventilation unit could be put in our attic. But our house has vaulted ceilings and there's just not room and I'm glad the ventilation unit ended up in our basement, because it was the primary point of access for all the service issues. So another decision is equipment location for the outdoor compressor unit (which is huge) and the indoor ventilation unit.
Major Decision Problem
We almost cancelled the job which we had already agreed to. The "returns". First according to our contractor there should be a "high" and "low" return for the system. These are single, very large returns. When we accepted the quote, the returns were going to go in a particular central wall, no problem! I was doubtful of this at the time. What happens is the guy doing the quote is not the guy doing the installation. The guy doing the installation could not put the returns where the guy doing the quotes had specified. The returns are also 400 square inches, 20" x 20" inches, wider than your typical stud spacing. So after a lot of somewhat heated discussion we decided the return ductwork could be put in the bathroom with the returns themselves in a central hallway (This could have been done better). The returns cannot be in the bathroom, if they were the door would be blown off if you closed it with system running. This "change" required my wife and I to get rid of the exiting sink and counter top, losing considerable space and storage, and put in a new smaller sink and mirror in the bathroom. So my wife and I redid some electrical, drywall, plumbing, a new fancy sink and base ($500), and fortunately we had left over matching wall paper. But the bathroom actually looks pretty good today.
Heat Pump installation
There were two people, sometimes three, in our basement for a total of six working days. They started out a little slow, worked more as time passed, and actually the last two days they were rushed, even though they left early the last day.
Admittedly our basement was a mess. So work was a little tough for the
installers. You can see in the photo at the top of the page I ended up
storing a bunch of stuff including furniture under a tarp below our deck.
We just had to make some space. Initially there was a lot of stuff to store
in our basement for the installation. It did rain so everything had to
come inside. The duct work takes up a lot of space, along with boxes of
flex vent XP, dampers, grills, and other miscellaneous ductwork..
Positive aspects of our heat pump system
The ductwork, and workmanship, were of high quality. The ducts are well insulated, both inside and out. This is important to avoid any condensation during air conditioning season. This will also quiet the system.
I think the selection of equipment is very good, Trane is well respected. Available documentation is a little limited.
Because we were buying both the heat pump and air ventilation unit at the the same the system warranty is extended to 10 years.
The installer met all the the manufacturers installation requirements.
Problems I've repaired
Thermostat mounting.
Condensate pump noisy
Condensate pump cord runs across floor.
Several balancing dampers do not function
Supporting flex duct KP properly. Requires supports 1 1/2" wide minimum.
Problems I've found
After startup a significant refrigerant leak. Unit freezing up repeatedly. Defective indoor coil.
Unbalanced auxiliary or backup heat.
Because of the design of a ductwork splitter almost all the heat from the auxiliary heating ( electric resistance coils ) goes up one side of the system heating the North side of the house, but returning ambient temperature air to the South side of the house. This was quite a surprise and had fooled me into thinking I had no auxiliary heat at all. Also, I think this quirk is confusing the thermostat. When it calls for auxiliary heat it first sees cool air then warm air. The aux. heat will actually cycle off prematurely, in my opinion, as if the thermostat thinks aux. heat has failed.
Final "commissioning"
The installation work was rather rushed the last couple days. The heat / ventilation system balancing consisted of waving hands in front of each vent and making sure air was coming out. It turned out I found one vent whose balancing damper was pretty much turned off. I've since found that several heat balancing dampers do not work.
The south west quadrant of the house was overheating.
The basement is to cold, not nearly enough air moving.
Problems after heat pump installation
No auxiliary heat.
Loud heat pump compressor noise after defrost cycle.
Thermostat configuration
Heat pump cuts off at 30 degrees.
Heat pump installation tips and suggestions
I'd recommend suggesting to your contractor that as part of your agreement there be a thorough walkthrough of your system once it's installed. The walk through would demonstrate the full functionality of every component in the system, especially all balancing dampers should work. All floor vents should open and close properly. There should be a balanced airflow throughout the house. If you requested your basement be heated, it should be, and there shouldn't be a hurricane of air flowing in and out of your basement door!
I will be finishing the content of this article soon, it's turned into quite a comprehensive review of our heat pump installation.
I hope this helps you with heat pump reviews and your choice, and making sure you choose a good heat pump contractor.
Bob