wp-graphql
domain was triggered too early. This is usually an indicator for some code in the plugin or theme running too early. Translations should be loaded at the init
action or later. Please see Debugging in WordPress for more information. (This message was added in version 6.7.0.) in /home4/carbonsw/public_html/carbonswitchcms/wp-includes/functions.php on line 6114wp-simple-firewall
domain was triggered too early. This is usually an indicator for some code in the plugin or theme running too early. Translations should be loaded at the init
action or later. Please see Debugging in WordPress for more information. (This message was added in version 6.7.0.) in /home4/carbonsw/public_html/carbonswitchcms/wp-includes/functions.php on line 6114Heat pumps are one of the most efficient ways to heat and cool a home. But can a heat pump system<\/a> work in the winter when the temperature drops below 20 degrees? <\/p>\n\n\n\n Contrary to popular belief, modern cold-climate heat pumps can heat a home efficiently even when the temperature drops below -10 degrees. At this temperature the best cold climate heat pumps<\/a> are still more energy efficient than furnaces and boilers.<\/p>\n\n\n\n Just ask the millions of homeowners in Scandinavia. People in Norway, Finland and Sweden are installing heat pumps at a faster pace than anywhere else in Europe. <\/p>\n\n\n\n You might be thinking, \u201cScandinavians do everything<\/em> better than the rest of the world.\u201d But some states in America are actually adopting heat pumps at an even faster rate than the countries listed in the chart above \u2014 even some of the ones with the coldest climates.<\/p>\n\n\n\n Last year, in Maine, there were 50 units sold per 1,000 households, inching it just a little higher than Europe\u2019s leading country, Norway. By comparison 23 units were sold per 1,000 households in the rest of the United States. <\/p>\n\n\n\n There\u2019s compelling evidence that heat pumps can save most homeowners a lot of money too. I recently used data from NREL\u2019s ResStock model to see how much money the average homeowner can save<\/a> by switching to a heat pump in various states. I discovered that the average homeowner in Maine \u2014 to use my favorite cold climate state as an example again \u2014 could save $718 per year.<\/p>\n\n\n\n In New York, a far more populous cold climate state, the average homeowner can save $637 per year. The millions of homeowners using fuel oil in the state could save $976 per year. <\/p>\n\n\n\n I could go on and on. Pennsylvania: $935. Massachusetts: $838. Ohio: $676. You get the point. There are a lot of cold places in this country where heat pumps are simply the best way to heat a home and save money in the process.<\/p>\n\n\n\n But why are there still so many contractors and homeowners that think heat pumps don\u2019t work in cold climates? My theory is that three myths are to blame:<\/p>\n\n\n\n To be clear, these are all myths. But like many falsehoods, their origins stem from seeds of truth. Sometimes the capacity of a heat pump doesn\u2019t meet the load of a home. In some climates and homes it isn\u2019t as cost-effective to use a heat pump. <\/p>\n\n\n\n In the rest of this article I want to debunk each of these myths. But I also want to go beyond the black and white answer and explore why some heat pumps work in cold climates and others don\u2019t. <\/p>\n\n\n\n Before beginning our mythbusting adventure, it\u2019s helpful to understand the basics of how heat pumps work<\/a> on a cold day. <\/p>\n\n\n\n Unlike traditional heating technologies like furnaces or electric baseboards<\/a>, a heat pump doesn\u2019t burn or use a fuel to generate heat directly. Instead, it uses a little bit of energy to run a compressor that effectively moves heat from one place to another.<\/p>\n\n\n\n While it might not seem like it on the surface, on a cold day there\u2019s actually some heat in the air outside. A heat pump takes some of that heat and moves it into your home. <\/p>\n\n\n\n This basic principle enables a heat pump to take in one unit of energy (in the form of a watt of electricity) and pump out three or four units of heat (usually measured as British Thermal Units, or BTUs<\/a>). In more technical terms, by using a little bit of energy to run a compressor, a heat pump can achieve a coefficient of performance (COP) of more than one. <\/p>\n\n\n\n If you\u2019re curious to learn more about the physics of this, I recommend watching this 8 minute video<\/a> and if you\u2019re really<\/em> curious, check out this 35 minute video<\/a>. <\/p>\n\n\n\n For now, the key things to understand are:<\/p>\n\n\n\n With all that in mind, let\u2019s start mythbusting. <\/p>\n\n\n\n The first myth to debunk is \u201cThe capacity myth\u201d which is the notion that heat pumps don\u2019t have enough capacity to keep a home warm on a cold day. <\/p>\n\n\n\n Earlier I mentioned two terms: load and capacity. To understand why \u201cThe capacity myth\u201d isn\u2019t true, it\u2019s helpful to understand these two concepts.<\/p>\n\n\n\n The heating load of a home is the amount of energy required to keep it at a comfortable temperature. <\/strong>As the temperature changes, the load changes. On a nice 70 degree day the load is basically zero. On a freezing cold day it\u2019s much higher; your heating simply needs to work harder to keep your home comfortable. <\/p>\n\n\n\n The load also depends on unique characteristics of the home like the amount of insulation or the type of windows and doors. A home built in 1850 with no insulation requires more energy than a brand new home. The load is just a technical way to describe and measure all of this. <\/p>\n\n\n\n The capacity is the amount of heat \u2014 or, in the case of air conditioning, cold \u2014 that a HVAC system can supply.<\/strong> If load is the leak at the bottom of your bucket, capacity is the faucet bringing in more water. <\/p>\n\n\n\n Heat pumps are unique compared to every other HVAC system in that they don\u2019t have a single fixed capacity. Whereas a furnace might have a fixed capacity of 100,000 BTUs every day of the year, no matter the weather, a heat pump’s capacity<\/a> could range from 40,000 to 60,000, for example. <\/p>\n\n\n\n If you think about it for a second, this makes sense. Earlier I mentioned that heat pumps effectively capture warmth from the air outside and bring it into a home. The lower the temperature drops, the less energy there is to move. Hence, the capacity goes down. <\/p>\n\n\n\n As long as the capacity doesn\u2019t drop below the load, the heating will work just fine. But if a contractor undersizes a system, then there\u2019s a good chance that on a really cold day it\u2019ll get uncomfortably chilly in the house. In the example above that\u2019d be about -7 degrees. <\/p>\n\n\n\n At that point, your home doesn\u2019t immediately become an ice-box. No, that\u2019s when backup heating strips kick on and your heat pump basically turns into a space heater. Using electric resistance heat like this isn\u2019t efficient, but given that backup heat is generally used less than 1% of the hours in a year, it doesn\u2019t impact operating costs very much. <\/p>\n\n\n\n In home energy, nothing is black and white. A low-capacity heat pump in a leaky home won\u2019t work. Even a good heat pump isn\u2019t sufficient to provide all your heating if you live somewhere that regularly gets colder than -22 F, which is when the best cold-climate heat pumps<\/a> start to tap out. <\/p>\n\n\n\n But for the vast majority of people in America, heat pumps can supply 100% of the capacity necessary to keep their home comfortable all year round. Most complaints about heat pumps not working in cold weather are the result of user error \u2014 often by the installer \u2014 not the underlying technology.<\/p>\n\n\n\n Earlier I mentioned that the magic of a heat pump is that it converts one unit of energy into three or four units of heat. But this ratio \u2013 referred to as the coefficient of performance (COP) \u2013 isn\u2019t a fixed number all the time. <\/p>\n\n\n\n The colder it is outside, the harder it is for a heat pump to effectively find any heat in the air and move it into your home. Hence, the lower the temperature, the lower the COP. <\/p>\n\n\n\n But a common misconception \u2013 we\u2019ll call it \u201cThe efficiency myth\u201d \u2013 is that at 30 or 40 degrees, the COP drops below one. If that were true then it would take one unit of energy to create 0.8 units of heat, for example. At that point it would make more sense to run a resistance heater or natural gas furnace since these systems convert anywhere from 80-100% of energy into heat. <\/p>\n\n\n\n However, that\u2019s not the case. Compared to the heat pumps of yesteryear, today\u2019s cold-climate heat pumps can achieve COPs of more than one even at very cold temperatures. At 30 or 40 degrees, many of them achieve COPs ranging from two to three. <\/p>\n\n\n\n Take a look at the chart below that shows the COP of a Mitsubishi cold-climate heat pump<\/a> during a series of tests in Alaska. As you can see the COP generally remains above one until about -10 degrees fahrenheit. <\/p>\n\n\n\n In other words, until the temperature reaches -10 degrees fahrenheit, this heat pump would perform more efficiently than any other piece of equipment. And how many hours a year is it really colder than -10 degrees fahrenheit where you live?<\/p>\n\n\n\n The takeaway: Today\u2019s heat pumps are the most energy efficient way to heat a home even in extremely cold weather. <\/p>\n\n\n\n Most people don\u2019t care about BTUs and COPs. They want to know how much something will cost them in dollars.<\/p>\n\n\n\n This is where the comparative analysis of all this stuff gets a little tricky. In America, energy prices vary widely depending on where you live. In Connecticut, electricity costs a little more than $0.20 per kWh. Those same electrons cost $0.10 per kWh in Louisiana. <\/p>\n\n\n\n Natural gas has a similarly large range. In Florida the average price of residential natural gas is about $2. In Idaho it\u2019s $0.65. In addition to that, every climate and home is different. Each one requires a different amount of energy to stay warm in the winter. <\/p>\n\n\n\n To estimate the cost of using different fuels and equipment in every home in America would require a supercomputer crunching millions of data points. Fortunately those exist. <\/p>\n\n\n\n<\/figure>\n\n\n\n
<\/figure>\n\n\n\n
<\/figure>\n\n\n\n
The three myths of cold climate heat pumps<\/h2>\n\n\n\n
How do heat pumps work in the winter?<\/h2>\n\n\n\n
<\/figure>\n\n\n\n
The capacity myth<\/h2>\n\n\n\n
<\/figure>\n\n\n\n
<\/figure>\n\n\n\n
The efficiency myth<\/h2>\n\n\n\n
<\/figure>\n\n\n\n
The money myth<\/h2>\n\n\n\n