Your HVAC system has a dedicated heating element. A water heater seems to serve a similar purpose as well. If you’re not familiar with how these two appliances work, you’re probably wondering if an HVAC system includes a water heater.
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The HVAC typically doesn’t include a water heater. The water heater is a part of your house’s plumbing system. However, a hybrid water heater or a heat pump water heater and a boiler that can simultaneously provide heat and hot water are instances of HVAC systems that include a water heater.
In this article, I’ll explain how HVAC systems with water heaters work to provide both heat and hot water for your home. I’ll describe how you can care for such systems to make them more efficient and extend their lifespan. I’ll also touch on the connection between HVAC and plumbing systems.
HVAC Systems With a Water Heater
A water heater heats the water supplied to the faucets, showers, washing machine, and dishwasher in your home. The HVAC system heats, cools, and conditions the air inside your house and supports ventilation. However, some HVAC systems have components that also heat water. Read on to find out about two such HVAC systems.
Hybrid Water Heater or Heat Pump Water Heater
Heat pumps usually heat and cool indoor spaces and are considered an integral part of the HVAC system. However, you can also use a heat pump to heat water. Such a device is called a hybrid water heater or a heat pump water heater.
Here’s how a heat pump water heater works:
- An evaporator coil inside the device contains a refrigerant. It draws in hot air from its surroundings and absorbs the heat.
- The captured heat is then moved to heat water stored in a closed tank to a certain temperature.
- Pipes connected to the heater tank move the water to the faucets, showers, dishwasher, and washing machine.
- The heat pump blows out the cold air.
A heat pump water heater is 2-3 times more energy-efficient than conventional water heaters that use electricity to heat water. That’s because the former does not generate heat to warm water; it merely transfers heat from one place to another.
Heat pump water heaters are more expensive to get and install compared to conventional storage water heaters. But these hybrid devices offset the high costs with substantially lower operating expenses.
Heat pump water heaters are available as integrated units fitted with water storage tanks. You can also retrofit a heat pump to make it work with your existing standard storage water heater. Keep in mind the following pointers during installation to make your heat pump more efficient:
- A heat pump water heater is ideal for homes in climates where the year-round temperatures remain between 40 °F (4.4 °C) and 90 °F (32.2 °C).
- These devices work most efficiently when installed in a warm or hot space because they work by extracting heat from the surrounding air. The best place to install such a device is the furnace room.
- Heat pump water heaters cool the air around it. So, install it in a space where there is excess heat.
- Ensure there is at least 1,000 cubic feet (28.3 cubic meters) of vacant area around the device. This ensures airflow into and out of the device is not obstructed.
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Hot Water Boilers
As components of HVAC systems, boilers generate heat for your home. Some boilers can also heat water that is then piped to faucets, showers, dishwashers, and washing machines. Here’s how a boiler works to provide heat for indoor spaces and hot water for your washing and bathing needs:
- A furnace within the boiler generates heat by burning a fuel source, such as gas, oil, or coal.
- The heat generated warms a heat exchanger.
- The exchanger heats the water that flows over it.
- The hot water is then circulated through pipes that pass through various areas of your home. The heat radiated from the hot water in the pipes warms the indoor air.
- The water in the pipes re-enters the boiler, by which time it has lost most of its heat. So, the heating process begins again.
- After being heated by the exchanger, some of the hot water flows through a coil to heat a mass of cold water in an enclosed tank.
- This newly-heated water from the tank flows through pipes and is made available for bathing, cooking, cleaning, and washing clothes via faucets and showers.
The furnace heats the water in steam boilers to turn it into steam. The steam travels through the pipes and reaches the radiators or convectors installed in the rooms of your home. The radiators or convectors give off heat to warm the room. After losing heat, the steam cools and condenses into water. The water then travels back to the boiler furnace to be heated again.
Boilers can heat water quickly. They are available in tanked and tank-less versions. The tanks hold cold water. The tank-less models provide hot water on demand. So, these models can heat water quicker than the tanked versions. They also require less space to be installed.
Some boilers also have hot water storage cylinders.
Maintaining HVAC Systems With Water Heaters
An HVAC system that includes a water heater is a considerable monetary expense. To ensure that the device works efficiently and lasts for years, you should follow the maintenance measures and schedule recommended by the manufacturers. Go over their guidelines.
Below are some basic maintenance measures that will prolong the life of your HVAC unit with a water heater:
- Keep vents and flues (if your system has them) clean and free of debris. This ensures unobstructed airflow and exchange.
- Check for leaks periodically. Leaks waste water, fuel, and electricity. Subsequently, they significantly increase operating costs.
- Check water levels every month. Running your unit when the water level is low can damage it.
- Lubricate the moving parts of your HVAC system regularly.
- Flush or drain out the water within the system every six months. Then clean the insides thoroughly. This prevents mold buildup and removes sediment, especially in the water heater tank.
- De-scale to remove any lime accumulation that tends to occur when hot water circulates through a mechanical device.
- Ensure the hot pipe of your water heater is well-insulated. This prevents loss of heat and saves energy. Insulate the heater as well to minimize heat loss.
- Operate your water heater at a lower temperature to save energy.
The Connection Between HVAC and Plumbing Systems
Although the HVAC and the plumbing systems perform separate functions, they are connected. You need to know about this connection because keeping your HVAC unit working efficiently also means maintaining the plumbing system in your home in prime working order.
Before explaining the connection, let’s specify what the plumbing system does.
The plumbing system consists of pipes that bring fresh water into and carry wastewater out of your house.
The HVAC system releases a considerable amount of water as it carries out its functions. This water has to be carried out of the building. The following two components of the HVAC system are connected to the plumbing system:
The cooling component of an HVAC system, or the central air conditioner, is also involved in reducing the humidity of a space. The device can condense several gallons of water on hot and humid days. The condensate flows out of the house through a pipe connected to the drainage system.
Standard furnaces have a single heat exchanger. High-efficiency furnaces have a secondary heat exchanger that extracts more heat by condensing the water vapor collected in the exhaust airflow section. The condensate flows outside the house through a pipe connected to the drainage system.
Although an HVAC system typically does not include a water heater, the ones that do provide many benefits to homeowners. You do not have to spend money on buying separate appliances and then spend some more on installation.
An HVAC unit integrated with a water heater, especially a unit with a boiler, is more energy-efficient than conventional water heaters. The key is to choose a model that is the appropriate size for your home and suits your climate.