Loving the passive solar effect on those sunny days, but often finding myself with a shiver on the cloudy/overcast days. That’s one of the annoying things about being a quadriplegic, I’m always cold unless it’s 76+ degrees, but I hate to keep my room that warm all the time because I know the sun will kick it up a notch any time it’s clear outside. So, I’ve been using an electric heater quite a bit this winter to avoid the 4 hour wait of heating the radiant slab up a few degrees. Everyone loves the toasty warm feet, and I love the energy storage/efficiency of the huge thermal slab, but it sure does take a long time to get it to temperature. Not a good thing when I’m cold!
Heat Pumps and Humongous Rebate/Incentives
So in the midst of all this electric heating I started to think about a better solution to my keeping warm needs. Seems that it was just in the nick of time, because our local utility recently did a media blitz plugging the incredible efficiency/cost savings of these new ductless heat pumps. And even better, they are providing a $600 rebate as an incentive for homeowners to purchase one, and the federal government is providing a $300 credit.
Decided I’d calculate out a few numbers to see if these heat pumps are really cracked up to all that they said.
Comparing a Heat Pump to a Radiant Electric Heater
By definition 1 Watt = 3.412142 BTU/hr
Output of my 1500 W Radiant Electric Heater
1500 Whr * 3.412142 = 5,100 BTU/hr
Contrast this to the new Fujitsu Halycon 15RLS2 inverter driven ultraefficient heat pump that puts out 14.01 BTU/Whr according to the Energy Star ratings and you would get 21,000 BTUs out of this same 1500Whrs of electricity
1500 Whr * 14.01 BTU/hr = 21,000 BTU
An increase of efficiency of over 400%.
The increase in savings ends up being even more than this because my utility company reduces the electricity rate for heat pump users from $0.15/KWhr to 0.11/KWhr for anything over 600 kWh. Figuring in this reduced electricity rate means I can run the electric heat pump and get the same amount of heat (BTUs) for approximately 1/5th the price of that radiant electric heater. Granted, this is rather overly simplistic, and doesn’t take into account the reduced efficiency of a heat pump at extreme low temperatures, but you get the point, they’re far more efficient/cheaper to run.
Comparing a Heat Pump To a High-Efficiency Oil Broiler
Let’s take this a bit further, and compare the price of the heat pump to my high-efficiency Pensotti Quatech Series Oil Boiler.
1 gallon of #2 fuel oil has 139,000 BTUs. At my boiler’s 88.6% efficiency thismeans my boiler is putting out 123,000 BTUs of heat from a gallon of #2 heating oil.
139,000 BTU * 88.6% = 123,000
At current fuel prices this is $3.47 for 123,000 BTUs of energy.
Contrast this to the Fujitsu 15RLS2 for 123,000 BTUs
123,000 BTUs / 14.01 BTU/Whr = 8.8 KWhr
8.8 KWhr at $0.11 KWhr = $0.97 for that same 123,000 BTUs
Please someone check my math here, because this seems absolutely incredible. The heat pump creates the same amount of heat as my high-efficiency oil boiler for only 28% of the price. WOW, and this only gets better as the price of oil goes up.
Still astounded by these calculations, and obviously very skeptical as to whether they’ll hold up in the real world, but if they do the savings will be considerable. Like payback in 3-5 years.
Couple additional things that sweeten the pot even further. Since I have all this overabundance of electronic gear, overzealous audio amplifiers, big TVs, incandescent lights at the moment (yes I know, shame on me) my power consumption is already over the 600 KWhr minimum for the heat pump discount. That means as soon as I hook the heat pump up, I’ll get the 26% discount from my electric utility for everything over 600 KWhr, even the excessive energy I use on all my electronics. Probably not the greenest/environmentally friendly of incentives, but still very real money.
And then there is the comfort. As a quadriplegic, when I get cold I feel absolutely miserable, like nerve pain, crazy intense contractures in my shoulders/neck, overall just not fun. The only way I can get this to go away is to get warm again. Now I’ll have a way to get warm again, and real quickly. I’ll be able to let my room/slab cooldown more at night because it won’t take so long to heat up when I want it to, and in the summer when it’s crazy hot and I’m overheating I’ll have a very quiet/highly efficient air-conditioner to cool me down. Really seems like I can’t lose with this upgrade!
Please, somebody, burst my bubble here, tell me my calculations are screwed up, anything! These new high-efficiency heat pumps just seemed so incredible, like FREAKING AMAZING, I can’t wait to get mine installed like yesterday!
February 1, 2013 – Our Fujitsu 15RLS2 unit got installed! Come read my my initial thoughts:
Fujitsu 15RLS2 Heat Pump Installed – My Initial Thoughts