Interest in Mini Split Heat Pumps in US has grown tremendously in the last 10 years. One major question homeowners have is how much it costs to heat with a ductless heat pump?
Moreover, there are still many questions regarding suitability of mini split heat pumps as efficient HEATING SYSTEMS in terms of operating costs, upfront installation costs, and heating in LOW WINTER temperatures.
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Cost To Operate A Mini Split Heat Pump Case Study In Boston, MA
Based on running multiple ductless heat pumps in heating mode in Boston MA winters since 2017, and collecting exact power consumption data on each zone (using Emporia Vue 2 Power Monitoring system), we will answer all your questions: how efficient ductless heat pumps are, do they work in cold temperatures, are they more expensive to operate vs GAS, OIL, Propane, etc.
IMPORTANT This guide is not about Central Heat Pumps, which are utterly not capable of heating a house in ambient temps below 35°F. Here we only look at mini-split / ductless heat pumps.
Also its important to state that we like it warm, and our set target temperatures are 75-76°F, and to achieve this, we usually have to set our heat pumps to 78-80°F with fan speed in Auto or High (depending how cold it is outside).
Finally, mini split heat pumps that we used in this “study” are two single-zone Fujitsu Extra Low Temp Heating (XLTH), which are designed to provide heat in ambient temps as low as -15°F. Our 3 units are all 9000 BTUs single zone systems – 9LZAH1 and 9RLS3YH. These are practically the same – one is “older” and no longer sold (9RLS3YH), and the 9LZAH1 one is the current high efficiency unit sold by Fujitsu.
Mitsubishi has a similar line-up known as Hyper-Heat, and will work in temps as low as -13°F.
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Note that another big reason for the growing interest in ductless heat pumps is because federal and state governments are pushing green & renewable energy initiatives, and heat pumps line up with these programs very well.
For example, states like MA, NY, NJ, CA and many others offer huge incentives & rebates (in some cases up-to $5000 or more), when you switch from Oil or Gas to ductless heat pump systems.
Does A Mini Split Heat Pump Work For Heating In Cold Weather?
As mentioned above, the Hyper Heat / Extra Low Temp Heating models do in fact produce heat when outdoor temperatures are as low as -13°F (for Mitsubishi) and -15°F (for Fujitsu). There is also an American brand – Cooper & Hunter which claims their Hyper Heat works in even lower temps of -22°F. However we have not personally tested those models. Still, our educated guess that they would be on par with Mitsubishi & Fujitsu.
Daikin recently added “hyper heat” models that are rated at -10°F for Heating.
LG has has been making LGRED ductless heat pumps which are rated for -13°F (same as Mitsubishi).
In real world application, we personally tested 3 different Fujitsu Hyper Heat / XLTH models – all 9000 BTU rated models. All models are tested in the Boston MA area, where average winter low temps are often around 5-10°F and get as low as -5°F to -10°F.
Our 3 test systems are able to easily handle the heat load when temps are above 10-15°F outside. As outdoor temperatures drop closer to 0°, the heating capacity of our 3 single zone units goes down, and units are struggling to keep indoor temps above 73° (with 80° – 82° set point).
When outdoor temps are below -5°F, the indoor temps are at around 69-70°.
Real Heat Pump Heating Use Case: The systems we use (in our house) are the smallest in Fujitsu’s lineup (9000 BTU rated cooling & 12000 BTU heating capacity) and are generally designed for 350-400 sq. ft. spaces.
However we use them in spaces that are 600-750 sq. ft. for each unit, which is way oversized. Still they do the job well. Only when outdoor temps fall below 5°F, they begin to work extra hard, to keep up with 80° set temperature, and decreased heating capacity.
One system that is installed in the 240 sq. ft. space, keeps it warm with ease even in -10°F.
More details about our setup and test systems here.
Is Ductless Heat Pump Heating Expensive?
It really all depends on your electricity cost, and whether you have solar or not. If you live in a state with low electricity cost (at or below US average of $0.141 / kWh) then heating with a mini split heat pump is very economical, even compared to natural gas!
While you can use our Heating Cost Calculator to get accurate numbers for your house, if we take our setup (about 2000 sq. ft. home with average to poor insulation), you would use about 9500-11000 kWh of electricity to heat your home with a high efficiency ductless heat pump.
At US Average electric rate of $0.141 / kWh (at the time of publishing), your seasonal cost would be around $1,339.50 to $1,551 ($223.25 – $258.50/month).
|US Avg:||$2.19 / Therm||$0.00 / Gal||$2.98 / Gal||$0.154 / kWh|
|Virginia:||$1.43 / Therm||$4.66 / Gal||$3.71 / Gal||$0.125 / kWh|
Is It Cheaper To Heat With Gas Or A Mini Split Heat Pump?
In most states high efficiency Gas Heating and Ductless Heat Pumps are on par in operating costs, except MA** where we had a 36% electric rate increase , since summer of 2021, and possibly NY, where ConEdison has filed a rate increase petition of about 17.6% – 28.1% for retail customers.
In Idaho, Utah & Montana, where Natural Gas is extremely cheap ($0.69, $0.90 and $0.98 per therm respectively), having a high efficiency boiler or furnace, would cost less to heat your home than a high efficiency ductless heat pump.
** MA: In January 2022 we had a MASSIVE price increase on electric rates of $0.05/kWh, combined with a “scheduled” winter price increase of about $0.03/kWh around Sep/Oct off 2021. As a result, our rate went from about $0.225 in the summer of 2021 to $0.305 – this is a 36% increase within 6 months!
Thanks MA law makers, and Elizabeth (The Corporate Enemy) Warren in particular, for making this happen! Taking care of MA residents has always been your priority.
In most other states, ductless heat pumps are on par with Natural Gas.
In states like DE, AR, KY, heat pumps are more economical than natural gas.
A benefit of having a whole-house multi-zone heat pump is that you also have a very efficient Air Conditioner, and when paired with solar, can completely eliminate your heating/cooling/electric bill!
Refer to our Gas and Electric costs table for heating energy cost in your state
Do You Really Save Money With A Mini Split Heat Pump?
You can save money (in some cases a LOT) with a mini split heat pump, if certain conditions are met:
1) Your electricity is relatively inexpensive OR you don’t have natural gas OR you have solar.
2) You need a new AC and heating system. For example a high-end Lennox Central Heat Pump costs about $25,000-30,000 to install (including a gas furnace), whereas a 5-zone Ductless system would cost about $18,000-21,000.
3) Your only other choice of heating fuel is Oil or Propane
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Not all of the above are required, but the more checkmarks you have, the more you save with a ductless heat pump.
Is Heat Pump Heating Cheaper Than Gas?
As mentioned above, in most cases natural gas and heat pumps are close in operating costs, when you compare high efficiency models.
If you have an old furnace (with direct vent into the chimney), you will actually be saving a lot of money by heating with a heat pump.
However if you compare an 95% AFUE condensing gas boiler to a mid range heat pump, or if your electricity costs over $0.25/kWh, then Natural Gas (if you have access to it) might be a better option.
Lastly, if you also need AC then a heat pump will serve a dual purpose (heating and cooling), saving you about $5000-7000 in extra equipment / labor costs to install a Central AC.
Electricity and Natural Gas rates by state (sorted by electric rates, low to high).
|District of Columbia||$0.137/kWh||$2.54/therm|