Perhaps your home, or a room within your home, is heated by an older fossil-fuel burning (e.g. natural gas) space heating system – or an old electric resistance heater. The modern way to heat homes is with heat pumps – which always provide space cooling as well.
There are two excellent reasons for the growing popularity of heat pumps:
- They are much more energy-efficient than electric resistance heating, most are more energy-efficient than older gas heaters, and the most energy-efficient heat pump models are as energy-efficient as the most expensive gas models;
- Heat pumps run on electricity, which is safer for the community and safer for the planet as compared with burning fossil fuels. PG&E reports that their electricity generation is over 40% renewable, and MCE offers 100% renewable electricity. Given that most climate scientists say that we need to stop burning fossil fuels right away, heat pump heating (along with solar) is the way to go!
Note that there are also heat pump water heaters – which like space conditioning type heat pumps – are the environmental and energy best choice (along with solar) for water heating.
Types of space conditioning heat pumps
- Window Units. These are relatively new. Expect lower installed cost compared to other heat pump types. But they take up window space, are relatively noisy, and are not as energy-efficient as some other heat pump types. However, they are certainly a positive environmental and energy step above using a room gas or electric resistance heater.
- Through-the-Wall Units. These have been around for decades, commonly found in vacation lodging. As with the Window Units, they are noisier and less energy-efficient than the heat pump types listed below. However, for a room remodel on a budget, these may be an option worth considering. Note that some through-the-wall AC units are electric resistance heaters with cooling, rather than heat pumps. Stay away from these – both because electric resistance heating is generally banned by the State’s building energy code due to its very low energy efficiency, and because your heating costs will be very high.
- Package Heat Pumps. Like the Window and Wall units listed above, Package units contain the condenser unit (equivalent to the outdoor unit of a residential AC system) and the compressor unit (the indoor unit where heat – or cool – is transferred to living spaces) in a single box. These are usually used on the flat roofs of commercial buildings. They can be used for residences, but these units are not as energy-efficient as the “Split” type listed below.
- Split Heat Pumps. These are called “Split” because they consist of the outdoor condenser unit, and the indoor compressor unit. Because the condenser unit is not directly at the living space (as it is in Window and Wall units), these systems are quieter than Window and Wall systems. Split Heat Pumps are also available in much higher energy efficiencies than Window or Wall units, and greater efficiencies than Package units as well.
Split heat pumps come in many variations. The simplest models have the indoor unit mounted on the inside of a wall (as shown in the photo). Other variations have the indoor unit mounted above the ceiling, with a grill in the ceiling to condition a single room. These small capacity heat pumps are sometimes referred to as “Mini-Splits”, reflecting their small size and capacity. Another Split heat pump variation is where the indoor unit is mounted in attic space, attached to ducts which lead to registers to provide conditioned air to many spaces – perhaps an entire home. Finally, there is the whole house “ductless” variation, where every major space has a separate indoor unit providing conditioned air without the need for ducts (which eliminates the possibility of losing conditioned air via leaky ducts).
If your home, or room, is not well insulated (both walls and windows), it’s always recommended to improve the thermal efficiency of the building before installing new space conditioning – both to reduce energy use, and so that the new system can be a smaller capacity while still meeting the comfort needs of the occupants.
Not all heating/cooling contractors have experience with heat pumps. It’s recommended that you receive detailed quotes (with system description and unit energy efficiency ratings) from at least three contractors with good working knowledge of the type(s) of heat pumps you are considering using, and with knowledge about the incentive programs available (rebates and tax credits) which may lower your costs.
Note that the new White House administration may elect to reduce or eliminate some or all of the Federal programs which are behind many of the available incentive programs. So taking advantage of these programs ASAP is recommended.
Resources:
- The Switch is, at On https://www.switchison.org/ca , provides a comprehensive list of rebates and tax credits – for both efficient heating systems and for making building energy-efficiency improvements.
- Personal Climate Action Ideas, at https://garyf8642.wixsite.com/climate-action-ideas by this article’s author. You will find information about heat pump water heaters on the Water Heating page, more types of heat pumps are described on the Space Conditioning page, and information about making homes more energy-efficient on the Building Energy Efficiency page.
Replies