Heating/Cooling – Offering New Higher Efficiencies at Competitive Pricing – “Mini-Split Heat Pumps” Offer Heating and Cooling In Place of Propane, Wood Burning Stoves, Baseboard Electric, and Even Natural Gas
Mini-split (also sometimes called “multi-split) heat pump technology has been perfected in Asia and Europe, places where homes often can’t accommodate central heating and air conditioning. In recent years the technology has become highly efficient and its pricing has dropped. Run with electricity, mini-splits are becoming competitive with natural gas in total cost. One reason for this is that they can have multi-zone systems that allow for different rooms or zones to be heated or cooled, while other parts of the house are not, thus reducing the total energy and electricity needed. With high efficiencies and the ability to operate from clean renewable energy (like solar), this technology can replace natural gas to reduce dependence on fossil fuels. Mini splits are ideal for households that would like to heat or cool limited areas of high use, like family room/kitchen areas, without expending energy to heat and cool the entire house.
Mini-splits are composed of an outdoor compressor and an indoor air handler, or “head.” Here is a sketch of how mini splits are installed:
While the indoor air handler may hang on the wall, some models and configurations can also be installed in the ceiling or wall where it is concealed behind vents.
Mini split heat pumps offer these advantages over centralized ducted heat pumps and natural gas furnaces or air con:
1) You can install different single or multiple head units to heat or cool “zones” or different rooms of your home separately. Why heat or cool your whole house when you are using only one or two rooms at a time? The cost of heating with efficient mini splits can be less than natural gas because you can only heat or cool the room or zone you are using in the house.
2) Mini split heat pumps are now available with very high efficiency. They are far more efficient (up to four times or more) than standard resistance coil heaters such as baseboard heating or ceiling heat.
3) Mini split heat pumps both heat and cool your home with the same equipment. A single thermostat or hand held remote can switch the same unit to either heat or cool the zone it serves.
4) These units are “ductless,” meaning they do not make use of the existing ducts or furnace space you may already have installed. This eliminates signficant duct efficiency losses. Moreover, installation costs and times are also reduced.
5) Mini split heat pumps use electricity, so they perfectly complement a solar array on your roof to reduce dependence on fossil fuels.
You need to have a licensed contractor install this technology. It is “ductless” and single head systems can usually be installed in one day or less, multi-head in 2 days or less. You should compare pricing between bidding contractors carefully, because pricing can vary a lot. Some big box stores like Costco may offer good installation packages for this technology through participating contractors. Some contractors specialize in mini split heat pumps. Obviously such firms have a lot of experience and may offer the best deals.
How Mini-Split Heat Pumps are Rated – What to Look For
There are three acronyms that indicate how efficient a particular mini-split performs. Look at the product literature for the mini-split you are considering and check its ratings using this information. The three acronyms are COP, HSPF, and SEER, all explained below. Note that the performance of different mini-splits is tested according to an industry standard, called 2008 standard AHRI 210/240, Performance Rating of Unitary Air-Conditioning and Air-Source Heat Pump Equipment that is applied to models from different manufacturers. That standard defines these acronyms:
COP – (Coefficient of Performance) This number, which usually ranges between 2 and 5 (the higher the number the better), tells how much heating/cooling energy the mini-split offers for each unit of energy it consumes. Put simply, if a unit has a COP number of 3, that means that it creates three times as much heating/cooling energy as it uses to do this work. This isn’t magic. Heat pumps don’t create heat directly from the electricity they consume. Instead, they move heat around to where it is needed. “Air to Air” heat pumps, the category that mini-spits fall under, efficiently move heat from the air outside your house to inside your house (in heating mode), or from inside to outside your house (cooling mode). They can heat your house even when the air outside is much colder than the air inside. Likewise, they can cool your house even when the air outside is much hotter than inside (just like an air conditioner does).
HSPF – (Heating Seasonal Performance Factor) This number, which usually ranges from about 7 to 14 (again, the higher the better) indicates the expected heating performance of a mini-split unit over an entire season (like winter!). Obviously, your heating bill in October might be much less than your heating bill in January. So this number indicates the expected heating performance of a heat pump in different conditions over time. It is especially indicative of how well the heat pump provides heating, as opposed to the next number, SEER, which indicates how well the heat pump provides cooling.
SEER – (Seasonal Energy Efficiency Ratio – ) – This number, which usually ranges from about 10 to 30 (again, the higher the better), is similar to the HSPF number, but is regarded as the best indicator of the cooling ability of a particular mini-split. In other words, a mini-split with a SEER number of 30 will be much more efficient than a mini-split with a SEER number of 15.
EER – There is also an acronym called “EER” which remains in wide use. It is sometimes used in product literature and is related to COP. The EER = 3.41214 × COP.
New Strategy for Mini Split Installation and Use
Due to the high efficiencies attained by newer heat pump models, some contractors simply recommend that for small to medium size houses (up to around 1600 ft2 or so) a single head “mini split” heat pump be installed in the most often used area of the house. A single heat pump may be able to provide the bulk of the heating and cooling needs of the house. If the homeowner finds that one unit is insufficient, then installing a second unit in a different area of the home can be undertaken. The reason for this approach is that is may save a lot of money. Many homeowners have found that a single unit can meet their needs, especially if it is supplemented in extreme weather by other systems that remain in place. Also, single head mini splits are more efficient that multi-head units, so long term savings in electricity are obtained by installing one or more single head units as opposed to multi-head units. Talk this over with your contractor and don’t hesitate to contact factory sales personnel to get the latest information on products.
This website does not promote any particular manufacturer of mini-split heat pumps. However, there are a few manufacturers that are leading the way toward ever greater heat pump efficiencies. Currently, Asian manufacturers such as Mitsubishi, Fujitsu, Daikin, Toshiba, and LG comprise a top list of manufacturers. There are several other manufacturers that offer economical, if less efficient mini split models. Those names include Pioneer, Gree, Senville, and others.
Here are some links to general information and specification sheets for some leading manufacturers:
News: Mitsubishi model MSZ-FH is now being installed widely in the market. The 9000 BTU unit has reached a 30.5 SEER benchmark. The data sheet for this new product can be seen at this website:
Listen to this podcast site from Renewable Energy World about heat pumps and mini-split heat pumps in particular.
Replacement for Burning Wood, Electric Baseboard, Propane, or Oil Heat
Mini-splits have gained popularity as a replacement for the above mentioned fuel supplies for heating homes. They have proven themselves in quite cold climates. A major supplier of mini splits in the Pacific Northwest tells me that ten years ago the technology was hardly known and HVAC contractors strongly resisted adopting it, preferring to stick with their old business models and products. But with new higher efficiencies and lower prices, the situation has rapidly changed in that region. Mini split heat pumps from leading manufacturers like Mitsubishi, Daikin, and Fujitsu are now being widely installed and have been embraced by consumers. Moreover, lower prices have made the business of installing mini splits more profitable and attractive to contractors, who now widely promote them instead of avoiding them. Mini splits have been a boon to households burning wood or propane, offering both heating and cooling, better air quality than wood burning, and lower costs than propane. The same supplier of mini splits in the Pacific Northwest says they now recommend use of small sized, but high efficiency models like the Mitsubishi MSZ-FH09NA in houses up to 1400 square feet or so. They say the higher performance of the new models allows that just one wall mounted air handler can often comfortably heat and cool entire houses up to that size, even in cold Pacific Northwest winters.
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