What is the best Heating System to replace my home’s current system?
Is it time to replace your home’s heating system? Residential heating systems are designed to operate anywhere from 15 to 20 years and if yours has been in use for 15 years or more, it’s likely time to replace it. Furnaces and other heaters lose efficiency due to age, which means it has to work harder, but can’t necessarily produce the heat it needs to. This results in excess energy use and substantially higher utility bills. An older heating system will also need more frequent and expensive service calls and repairs. A new, energy-efficient heating system can solve all these issues. But what type of home heating system should you choose for your new home or to replace your current heating system?
Types of Residential Heating Systems
The thought of replacing your home’s existing heating system with something new and different could be a little unnerving. After all, you were well acquainted with your current heater and its functions. But, home heating technology has come a long way and it’s worth it to learn about your options and the benefits of each type of heating system available on the market today before making a decision.
Forced Air Furnaces
This is the most popular form of heating system. The furnace pulls cool air from inside the home through return air ducts to the burner system and heat exchange. The heated air is then forced through the ductwork to vents and ducts to circulate into the house.
Furnaces are favored by those who like warm instant comfortable heat. Due to the burning of fossil fuel, the intensity of the heat production surpases that of mechanical heat pump heat.
Pros: Forced air furnaces can be fueled by fuel oil, natural gas or propane (LP). The use of fossil fuels allows these furnaces to produce a hotter supply air to heat the house. Also, this heating output is not effected by the outdoor temperature. Furnaces have come a long way. Even the oil burning furnaces have become more efficient over time. With new technology such as 2 stage oil pumps and gas valves, ECM and variable speed blower motors, and dual heat exchangers, newer furnaces are energy-efficient, quiet, and reliable.
Cons: Forced air furnaces take up more space than other heating systems. Ductwork is required and can be costly to install or rework. Annual service will be more likely required on furnaces due to having to clean the soot or byproducts of combustion. Also, if oil is used, annual service will be required to change oil filters and to have the burner checked and cleaned as appropriate. If your goal is to steer away from burning fossil fuels in your home to heat your house, a furnace is not what you want. You will need to look at the heat pump systems.
Boilers come in many different types.
Overall, they can be classified into 2 main types – hot water and steam boilers. Steam boilers heat water into steam and only the steam rises into the piping to each room’s radiator. The piping is installed a bit differently to allow the steam to travel and the condensate formed when the steam cools to drain back down to the boiler or traps.
Hot water boilers are filled with pressurized hot water and a circulator(s) pump sends the hot water around the piping loop to all the heat transmitters. This water reaches temperatures of 180F.
The biggest difference between boilers and most other heating systems is that boilers do not use ductwork to move air throughout the house. Instead, boilers use piping to send either hot water or steam to terminal heating units like radiators, baseboards, or even in-floor radiant heating. Boilers can, however, be used to supply heat to coils installed in ductwork so that a fan coil can blow air past the hot coil and thereby heating your home.
Much like with furnaces, boilers can use various fossil fuels to heat. Oil, natural gas and propane (LP) can all be used depending on the type of boiler.
Oil boilers will not tend to reach the high efficiencies that gas boilers achieve. With gas boilers – efficiencies up to 95%+ can be obtained. These boilers are designed to use the exhaust gasses to further heat the water before escaping outside through the flue.
Another type of boiler – the “combi” boiler, can actually be used to heat your home and heat your domestic potable hot water all in one unit. These combi boilers are offered in oil, natural gas, and propane (LP).
Wall mount boilers take up another type of boiler technology. These boilers are very compact, and light weight compared to conventional floor standing boilers. These are great solutions for homeowners wanting to free up floor space.
A special flue is installed consisting of PVC or other high temperature rated plastic. Most of these boilers are moving towards condensing. Meaning that the flue gases are re-used to further heat the house and the expelled flue gases are much cooler when they travel out of the house through the flue piping. This cooler exhaust gas condenses and moisture drains back toward the boiler to be drained to a drain pipe or an open floor drain.
These boiler are more efficient by utilizing more of the heat that is generated by burning fuel to actually heat your home.
Pros: Boilers can be fueled by fuel oil, natural gas or propane (LP). The use of fossil fuels allows boilers to produce a hotter supply heating temperature to the house. Also, this heating output is not affected by the outdoor temperature. Boilers have come a long way too. Even the oil burning boilers have become more efficient over time. A benefit of boiler heating over furnaces is that boiler heating works through radiation and convection not forced air – so the indoor air doesn’t get as dry which improves indoor air quality. Another benefit of boiler heating is that in new construction or retrofit applications, in-floor piping can be installed, and the boiler sends hot water through the floor. This provides an extremely comfortable heating, as you are heating the floor itself so it is warm to your feet, but it also radiates up and heats the air in the room as well.
Cons: If your goal is to move toward electrification, the boiler is not the solution for you. Also, if you don’t already have a boiler in your house, installing a boiler will not be a practical solution. You will have to install the piping throughout the house hidden in the walls, floors, and ceilings. The exception would be if you wanted to install a boiler to heat a cold basement floor, or if you wanted to provide hydronic heating to a new addition or garage. Another disadvantage to boilers as like with furnaces, is you must be comfortable with fuel combustion in your home. This includes monitoring that safe combustion is occurring, and carbon monoxide is not entering your home. Proper flue exhaust and chimney condition is also important to monitor, especially with oil boilers where soot may build up.
Heat Pump Systems
Heat pump systems do not use fossil fuels to produce heat. Rather, they utilize a compressor and refrigerant to make heat. This is referred to as mechanical heating. Mechanical heating is considered one of the most efficient forms of heating.
Traditional Style heat pumps
Most heat pump systems use an outdoor unit to heat – except for geothermal systems. Using a compressor and refrigerant, the outdoor unit actually extracts heat from the air it pulls through its condenser coil. Its ability to mechanically heat your home is impacted by the outdoor temperature. For traditional heat pumps systems, once a certain outdoor temperature is reached (ex: 40F), the heat pump can no longer provide the mechanical heating required to heat your home. At that point the system’s backup electric heat kicks in to supplement the less expensive mechanical heating. During this operation, electricity is being consumed to operate the mechanical heating as well as the electric backup heat all at the same time. As most of us know, backup electric resistive heat is considered the most expensive form of heat and has a significant impact on the electricity bill for homeowners. The more this backup electric runs in the winter, there will be a noticeable increase in the monthly electricity bill.
There are some types of heat pump systems that due to their unique engineering, they can keep up with heating your home even on the coldest days without dependence on electric resistive backup heat. As discussed below, these systems are the Mini/Multi Split and Geothermal ground source heat pumps.
Mini/Multi Split Systems – both ductless and ducted systems
This type of home heating HVAC system has a special design which allows its outdoor unit to provide mechanical heating for your house down to single digits outside. In the right application, these systems can effectively heat a house without backup electric heat. Each room, or zone, has its own indoor unit(s) – either ductless or ducted – that maintains the space temperature with a thermostat.
There are several configurations of the indoor unit. For ductless units there are wall mounted, ceiling cassette, floor standing units. For ducted units there are traditional style vertical and horizontal air handers (that can be used to replace an existing air handler) and “slim” style ducted air handlers which are great for small spaces like low attics and knee wall areas.
“Mini” split systems consist of an outdoor unit compressor/condenser and 1 indoor air-handling unit evaporator. This system is also commonly referred to as a one-to-one. Each room unit has its own separate outdoor unit heat pump.
“Multi” split systems consist of an outdoor unit compressor/condenser that feeds multiple indoor units. This system is ideal when there will be multiple indoor units.
Pros: Mini split systems don’t take up much space (both the outdoor and indoor units) and you don’t need any ductwork (with the ductless types). There are numerous options for indoor units to suit the needs and tight spaces you might have. Mini split systems are a highly-efficient way to keep rooms warm in winter and cool in summer as long as your house is sufficiently sealed and insulated.
Cons: One drawbacks of mini split systems is their initial cost. However, it’s easy to recoup that investment through energy savings. A second drawback is that for homeowners who want to convert to ductless systems, they will have to make provisions for installing and routing all of the refrigerant and wiring from the outdoor unit to each indoor unit location. Walls and ceilings may have to be cut open and chases might be required to accommodate this. However, this may be alleviated by installing the refrigerant piping along the outside of the house and installing cosmetic covering.
Geothermal Ground Source Heat Pumps
Which Home Heating System Is the Best Choice for Your New System?
After reviewing all the types of home heating systems listed above, you might be wondering which one is right for you. When making the decision, take into consideration initial costs of the unit as well as installation. Keep in mind that if you need ductwork or pipes installed, your costs will be significantly higher. You’ll also want to consider the fuel source for your new heating system. Equally important is to check both federal and local incentives and tax credits. In some cases, these incentives can significantly reduce the cost of converting to a more energy efficient system. Consult an HVAC professional you trust for advice and help choosing your next home heating system.