Buying a New Home in Raleigh - Saving Energy
Tankless Water Heaters
Also called "Demand Water Heaters" or "Instantaneous Water Heaters", tankless water heaters are becoming more common. Demand water heaters don't use a storage tank - instead, water is heated as you need it.
How Do Tankless Water Heaters Work?
Turn on the hot water to take a shower or wash some dishes, and cold water will travel through the pipes - until it reaches the tankless water heating unit. At that point, a gas burner heats the water as it goes through a series of loops. The result is hot water - at a rate of 2 to 5 gallons per minute.
How Much Hot Water Can a Demand Water Heater Produce?
There are a wide variety of tankless water heaters on the market today. Most provide hot water at a rate of 2 to 5 gallons per minute. This means that a typical full house water heater can probably support two users at the same time - say a washing machine and a shower, but not more than that.
On the other hand, multiple uses on a standard water heater can cause the hot water tank to empty, after which users must wait for it to reheat.
Should I Get an Electric or Gas Tankless Water Heater?
In the state of North Carolina, Progress Energy advises against purchasing an electric water heater. A typical standard electric water heater can use as much as 4500 watts of electricity - but an electric tankless water heater can use as much as 28,000 watts, which can cause a serious problem with the electrical supply. And Progress Energy is holding homeowners liable for any repairs or upgrades that might be required because of such a system!
Are There Ways to Increase the Amount of Hot Water Produced?
One way to increase the amount of hot water produced can be to install a small tankless water heater unit at each appliance or area that might need additional hot water, such as a hot tub, bathroom, dishwasher, or even as a booster for a solar water heating system.
How Much Heat Should the Tankless Water Heater Add to the Water?
Since ground temperature stays a standard 50-55ºF, you should assume that your incoming water is at that temperature. For nearly all uses, water should be heated to 120ºF. Thus you'll want a water heater that supports a 70ºF rise in temperature. If your dishwasher doesn't have an internal heater, you may want your water heated to 140ºF, a 90ºF rise in temperature.
There are a variety of tankless water heaters available, from companies like these:
- Stiebel Eltron USA
- Rheem Manufacturing
- Eemax, Inc.
- Noritz America Corp.
- Takagi Industrial Co.
- Bosch USA
- Bradford White Corp.
- Paloma Industries
- Chronomite Laboratories Inc.
You can request your builder install a specific system, or can ask what they normally install. Most good building contractors will take into account the size of the home and the number of bathrooms, and install a system they have found to be cost effective yet efficient.
How Much Does a Tankless Hot Water Heater Cost in the Raleigh Area?
In the Raleigh/Durham/Chapel Hill area, typical quotes for the system plus installation during the new home building process can be anywhere from $2000 to $4000 more than a typical standard tank water heater, depending on the size of the home and the type of system.
How Much Money Does a Tankless Hot Water Heater Save?
According to the U.S. Department of Energy, a tankless, or demand, hot water heater can save 24-34% more energy for homes that use 41 gallons of hot water or less daily. And hot water usage generally accounts for 14-25% of the total energy consumed in a home. Find out more here.
How Do I Get a Tankless Water Heater Installed in My New Home?
Ask your builder, before constructions starts if possible, if they offer tankless water heaters. If you have a specific brand and style in mind, ask for a price quote for the heater and all required installation (often larger gas lines will be required, and other changes will need to be made as well).
Tankless hot water heaters are becoming more common, but are not yet included in standard building practices, mainly due to the cost involved. But they can be a great choice to save long term energy costs and reduce reliance on natural gas, propane, or electricity.
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