Types of Water Heaters
Before purchasing a water heater it is always a good idea to know the different types and what will work best in your home.
- Conventional storage water heaters offer a ready reservoir of hot water
- Tankless or demand-type water heaters heat water directly without the use of the storage tank.
- Heat pump water heaters move heat from one place to another instead of generating heat directly for providing hot water
- Solar water heaters use the sun’s heat to provide hot water
- Tankless coil and indirect water heaters use a home’s space heating system to heat water
Conventional Storage Water Heaters
Conventional storage water heaters are the most popular water heating system and offers a ready reservoir of hot water ranging from 20 to 80 gallons. It operates by releasing hot water from the top of the tank when you turn on the hot water tap. Cold water enters the bottom of the tank, replacing the hot water to ensure the that the tank is always full. Storage water heater fuel sources include natural gas, propane, fuel oil and electricity.
Energy can be wasted even when a hot water tap isn’t running since water is constantly being heated in the tank. This is called standby heat loss. Some of these water heater storage models have a heavily insulated tank, which significantly reduces standby heat losses and lower annual operating costs. Look for models with tanks that have a thermal resistance, or R-Value, of R-12 or R-25.
Proper insulation depends on many factors including fuel type, climate, local building code requirements and safety issues, especially concerning the combustion of gas- and oil-fired water heaters. It’s recommended to have a qualified plumbing and heating contractor install your storage water heater.
Before buying a new water heater, consider the following:
- Size and first hour rating
- Fuel type and availability
- Energy efficiency and costs
The lowest-priced storage water heater may be the most expensive to operate and maintain over a lifetime, while an oversized unit, although alluring, may carry a higher purchase price and increased energy costs due to higher standby energy losses.
Tankless Water Heaters
Tankless water heaters are also known as demand-type or instantaneous water heaters, which provide hot water only as needed. These do not produce the standby energy losses associated with conventional storage water heaters and can save you money. Although gas-fired tankless water heaters tend to have higher flow rates than electric ones, they can waste energy if they have a constantly burning pilot light. This can sometimes offset the elimination of standby energy losses when compared to a storage water heater. In a gas-fired storage water heater, the pilot light heats the water in the tank so the energy isn’t wasted.
The cost of operating a pilot light in a tankless water heater varies from model to model. If you purchase a water heater that uses a standing pilot light, you can always turn it off when it is not in use to save energy. Also consider models that have a intermittent ignition device (IID) instead of a standing pilot light. This device resembles the spark ignition device on some gas kitchen ranges and ovens.
Tankless water heaters heat water directly without the use of a storage tank. When a hot water tap is turned on, cold water travels through a pipe into the unit. Either a gas burner or an electric element heats the water. As a result, tankless water heaters deliver a constant supply of hot water and you don’t need to wait for a storage tank to fill up with enough hot water. however, the water heater’s output limits the flow rate.
Typically, tankless water heaters provide hot water at a rate of 2-5 gallons per minute. Gas-fired tankless water heaters produce higher flow rates than electric ones. However, even the largest gas-fired model cannot supply enough hot water for simultaneous, multiple uses in large households. For example, taking a shower and running the dishwasher at the same time can stretch a water heater to its limit. You can install two or more tankless water heaters connected in parallel for simultaneous demands of hot water to overcome this problem. You can also install separate tankless water heaters for appliances that use a lot of hot water in your home.
Other applications for demand water heaters include the following:
- Booster for appliances , such as a clothes washer or dishwasher
- Booster for a solar water heating system
- Remote bathrooms or hot tubs
The initial cost of a tankless water heater is greater than that of a conventional storage water heater , but tankless water heaters will typically last longer and have lower operating and energy costs, which could offset its higher purchase price. Most tankless water heaters will have a life expectancy of more than 20 years and have easily replaceable parts that extend their life by many more years. In contrast, storage water heaters last 10-15 years.
Before buying a tankless water heater, consider the following:
- Fuel type and availability
- Energy efficiency
Heat Pump Water Heaters
Heat Pump water heaters use electricity to move heat from one place to another instead of generating heat directly. Therefore can be two or three times more efficient than conventional electric resistant water heaters. heat pumps work like a refrigerator in reverse in order to move the heat.
While a refrigerator pulls heat from inside a box and dumps it into the surrounding room, a stand-alone air source heat pump water heater pulls heat from the surrounding air and dumps it into a tank to heat water, at a higher temperature.
Heat pump water heaters require installation in locations that remain in the 40°-90°F range year-round and provide at least 1,000 cubic feet of air space around the water heater. Cool exhaust air can be exhausted to the room or outdoors. Heat pump water heaters will not operate efficiently in a cold space because they tend to cool the space they are in. You can also install an air source heat pump system that combines heating, cooling and water heating. These combination systems pull their heat indoors from the outdoor air in the winter and from indoor air in the summer. Because they remove heat from the air, any type of air-source heat pump system works more efficiently in a warm climate.
Before buying a heat pump water heater, consider the following:
- Size and first hour rating
- Fuel type and availability
- Energy efficiency
- Overall costs
Heat pump water heaters generally have higher initial costs than conventional storage water heaters. However, they have lower operating costs, which can offset their higher purchase and installation prices.
Solar Water Heaters
* (ACE HI PLUMBING, HEATING & AIR, INC does not repair or install solar water heating systems)
Solar water heaters are also called solar domestic hot water systems. This can be a cost effective way to generate hot water for your home. They can be used in any climate, and the fuel they use – sunshine – is free.
There are two types of active solar water heating systems – direct and indirect circulation systems. Direct circulation has pumps that circulate household water through the collectors and into the home. They work well in climates where it rarely freezes. Indirect circulation has pumps that circulate a non-freezing heat-transfer fluid through the collectors and heat exchanger. This heats the water that then flows into the home. This is more common in climates prone to freezing temperatures.
There are two types of passive solar water heating systems. Integral collector-storage passive systems work best in warmer climates. And then there’s a thermosyphon system which water flows through the system when warm water rises as cooler water sinks and also this type of system generally costs more.
Most solar water heaters require a well-insulated storage tank and have an additional outlet and inlet connected to and from the collector. In two-tank systems, the solar water heater preheats water before it enters the conventional water heater. In one-tank systems, the back-up heater is combined with the solar storage in one tank.
Solar water heating systems almost always require a backup system for cloudy days and times of increased demand. Conventional storage water heaters usually provide backup and may already be part of the solar system package. A backup system may also be part of the solar collector, such as rooftop tanks with thermosyphon systems. Since an integral-collector storage system already stores hot water in addition to collecting solar heat, it may be packaged with a tankless or demand-type water heater for backup.
Before buying a solar water heating system, consider the following:
- Estimate the cost and energy efficiency of a solar water heating system
- Evaluate your site’s solar resource
- Determine the correct system size
- Investigate local codes, covenants and regulations
- Understand the various components needed
- Heat exchangers
- Heat-transfer fluids
Tankless Coil & Indirect Water Heaters
Tankless coil and indirect water heaters use a home’s space heating system to heat water. They’re part of what’s called integrated or combination water and space heating systems.
A tankless coil water heater provides hot water on demand without a tank. When a hot water faucet is turned on, water is heated as it flows through a heating coil or heat exchanger installed in a main furnace or boiler. Tankless coil water heaters are most efficient during cold months when the heating system is used regularly but can be an inefficient choice for many homes, especially for those in warmer climates.
Indirect water heaters are a more efficient choice for most homes, even though they require a storage tank. An indirect water heater uses the main furnace or boiler to heat a fluid that’s circulated through a heat exchanger in the storage tank. The energy stored by the water tank allows the furnace to turn on and off less often., which saves energy. If an indirect water heater is used with a high-efficiency boiler and well-insulated tank, can be the least expensive means of providing hot water, particularly if the heat source boiler is set to “cold start.”
ACE HI PLUMBING, HEATING & AIR, INC. can help you to find the right water heater for your home. If you need to schedule an installation call us today at 970-667-0300. We provide 24-hour emergency service in the Northern Colorado Area.