SEER v HSPF v COP (& SCOP): Understanding Heat Pump Ratings
Many people are considering making the switch to a heat pump, for a variety of different reasons, including the heat pump grants available in Canada and the USA to offset the cost and the potential cost savings of buying and installing a single unit that can both heat and cool homes efficiently. Heat pumps are certainly less expensive to operate than other forms of electric heating like noisy baseboard heaters or electric furnaces, and despite the name they are all air conditioning units too. The cost of maintaining a heat pump combined central heating and cooling system is also less expensive than the cost of maintaining separate central heating and cooling systems, although there are different types of heat pumps as explained here.
Some people are making the switch to heat pumps because their impact on the environment is potentially much less than a traditional central heating and cooling system fuelled by fossil fuels like natural gas or heating oil. Because they use less energy, their carbon footprint is much lower, and as we've explained before, while just how Green they are depends on how sustainably produced the electricity is in the grid where the unit is operating, once installed if the grid adopts an increasing level of renewable energy then so do the households using it, automatically and progressively. This is why North America and Europe is electrifying homes and removing fossil fuels - especially heating oil and natural gas. Regardless of the reason why a homeowner has decided to choose a heat pump, as part of that decision it's good to understand how heat pumps work and how to compare them to see which heat pump is going to be best for their needs.
SEER vs HSPF vs SCOP ratings for heat pumps - the history behind the acronyms
Once it's decided that this kind of combined heating / cooling system might be of interest, now all that's left is to choose the best heat pump, right? Well, much like vehicles, sports teams, holiday destinations or the best fast food restaurant, there are a lot of different opinions out there, so making the very best choice of heat pumps depends on lots of variables as we discussed here. This is also confused by many manfacturers who are capitalizing on the increased popularity of heat pumps and have developed their own exclusive models too, saturating the market with different choices of heat pumps, most of which have their marketing department busily coming up with some exclusive acronym for a feature they can claim is the reason why their heat pump is the absolute best! However, help is at hand, various Government bodies decided that we needed help separating the marketing hype from reality, and that more efficiency was better - and so official heat pump performance ratings were born, starting with:
COP ratings for heat pumps
COP ratings came along much earlier than SEER or HSPF ratings, as the theory behind "heat engines" first became a subject of debate and experimentation after Nicolas Léonard Sadi Carnot - a French engineer - came up with the theoretical concept of the "Carnot heat engine" in 1824 having considered how steam engines worked by turning liquid into gas that had a higher level of energy and that could transfer this energy into motion. COP therefore stands for Coefficient Of Performance - which is a basic measure of outright heat pump performance under static conditions. In a 100% ideal case the maximum COP is 8.8. But in practice, it’s lower, much lower, in fact, the highest COP a heat pump can achieve is about 4.5, and any heat pump with a COP of above 3 is said to have a very high energy efficiency. However, the COP rating on it's own isn't that meaningful, as it doesn't allow the easy comparison of heat pumps under very cold, or very hot conditions - for all the kind of reasons that I'm not nerdy enough to get into here.
SCOP ratings for heat pumps - like COP, but more like SEER!
In 2013, SCOP or Seasonal Coefficient Of Performance was introduced. While COP is a measure of energy efficiency for a heating or cooling device, what SCOP rating is looking to achieve is to objectively measure energy efficiency over the winter season (for heating) and summer season (for cooling). This means that basically, the relationship between SCOP and COP is the same as with SEER and EER (that few people mention any more). SCOP has still considered a very new methodology of measuring seasonal cooling and heating efficiency. As such, you will rarely find the SCOP ratio on older devices.
SEERs ratings for heat pumps
SEER regulations were first put into place in 1992 when President Bush signed the Energy Policy Act. At that time, federal regulations required a minimum SEER rating of 10 for heating and air conditioning systems. The national rating requirement rose and fell over the next couple of decades, setting at 13 until 2011. In that year, the US Department of Energy established regional SEER rating standards, understanding that the amount of energy used for air conditioning varied in different parts of the country. For example, the Southern region has a longer warm-weather season than the North, so AC units run longer and use more energy to cool homes in the region.
HSPF ratings for heat pumps
Size is one consideration you need a heat pump that will be able to provide adequate amounts of heat and cooling to all of the rooms in your home. Usually, it is worth calling out a contractor for advice on choosing the correct size of heat pump.
Size is only one consideration, however. You need an efficient heat pump that is right for the climate you live in. That is where SEER and HSPF enter the picture.
First, consider SEER. This stands for Seasonal Energy Efficiency Rating. The SEER number lets you know how energy efficient the heat pump is at cooling your home. By law, a heat pump has to have a SEER rating of at least 13, but the rating scale goes as high as 21. The higher the number, the more efficient the cooling provided by the system.
HSPF is the Heating Seasonal Performance Factor, and it of course refers to the efficiency of the heating of the pump. HSPF ratings are required to be at least 7.7 but can go up to 10.
What do these numbers mean to you? You can use these ratings to choose a heat pump designed to meet your needs. High SEER ratings mean that the heat pump cools air efficiently, so if you live in a hot climate, a high SEER number is important. On the other hand, high HSPF ratings indicate effective heating and are ideal for cold climates.
Let HSPF ratings and SEER ratings help you choose a heat pump that will give you the kind of temperature control you want over your home.