If you know how an air conditioner works, you already know a lot about how a heat pump works, because heat pumps and air conditioners operate in similar ways.
Heat pumps are a unique kind of home comfort system, because they can do the work of an air conditioner and some of the work of a furnace.
Traditionally heat pumps have worked best in moderate climates. Here in the GTA they have been limited to effective use during the cooling season and the heating “shoulder” seasons of the spring and fall.
Traditional heat pumps have required air source temperatures of zero degrees Celsius or higher in order to operate, this requirement meant that they could provide cost effective heat for 40 percent of the heating season – but the rest of the season required the use of a primary heating source such as a furnace. With the recent introduction of hyper-heat inverters newer heat pump systems can operate at temperatures as low as -40 Celsius.
Heat Transfer and Air-Source Heat Pumps
There are many different kinds of heat pumps, but they all operate on the same basic principle of heat transfer.
Heat transfer means that rather than burning fuel to create heat, a device moves heat from one place to another. Heat naturally flows downhill, which means that it tends to move from a location with a high temperature to a location with a lower temperature.
A heat pump uses a small amount of energy to switch that process into reverse, this pulls heat out of a low-temperature area, and pumps it into a higher temperature area.
One of the most common types of heat pumps is the air-source heat pump, which takes heat from the air outside your home and pumps it inside through refrigerant-filled coils. Inside this basic heat pump, you'll find two fans, coils, a reversing valve and a compressor.
The reversing valve is a very versatile part of a heat pump. It reverses the flow of the refrigerant, so that the system begins to operate in the opposite direction. Instead of pumping heat inside your home, the heat pump releases it, just like an air conditioner. The refrigerant now absorbs heat on the indoor side of the unit and flows to the outside, where the heat is released and the refrigerant cools and flows back indoors to pick up more heat.
Home heat pumps are usually "split" systems with an outdoor and indoor component installed through the wall. The indoor coil is usually mounted above a furnace or air handler system.
With proper design, air-source systems work well with other types of indoor heating systems to offer a carbon free heating option during our local temperate seasons – more of the season is covered if you choose a low temperature (hyper-heat) system.
Before Choosing A Heat Pump
Before you choose a heat pump, you will need to consider what kind of supplemental or backup heating you will use when the heat pump can't work efficiently. Many heat pumps use supplemental electrical heating a gas furnace or a hydronic coil matched with a tankless water heater or boiler.
Ground-source heat pumps are better dehumidifiers than normal air conditioners, because these systems typically have a larger, flat return coil that conditions and dehumidifies more air than the corresponding coil in an air conditioning system. Air-source heat pumps have about the same dehumidifying capabilities as air conditioning systems. You will need to consider any humidifying or dehumidifying needs your home has and select your system accordingly.
What to Look for in a Heat Pump
When you start shopping for a heat pump, there are a few things you need to look for. First, manufacturers rate the efficiency of most heat pumps in two ways: SEER and HSFP ratings. Higher SEER and HSFP ratings indicate a more efficient unit.
- SEER stands for Seasonal Energy Efficiency Rating, and is a ratio of how much energy (measured in BTUs) is pumped outside in cooling mode divided by the electricity used (in watts) for cooling. Look for a SEER rating between 14 and 18.
- HSFP stands for Heating Seasonal Performance Factor. It calculates the ratio of energy pumped indoors for heating to energy used for heating, but it's a more complicated equation than the SEER rating because it also takes into account supplemental heating needs and the energy used to defrost the unit. Look for an HSFP rating between 8 and 10.
Your Encore Home Comfort Advisor will take the time to ensure you find the right equipment for your home. Contact us today for you no obligation appointment.
