Power-Vented Water Heaters
How Do They Work?
Power-vented water heaters use indoor air, but use a motor. The venter motor is mounted on top of the heater and used to exhaust the flu gases. Because the heater creates its own pressure using a venter motor, it’s not vulnerable to negative pressure inside the home. Power-vented water heaters use PVC and go through the side of your home.
This water heater has grown in popularity as homeowners gravitate toward more energy-efficient devices. It has an energy efficiency of 70%, so it needs a venter motor to properly exhaust the heavier and cooler flu gases. These heaters store water in a tank where it is kept warm until needed for use. This means that energy is being used to keep water heated even when you don’t need it.
By using exhaust from the home’s existing venting system, these heaters save energy and promote improved air quality and pressure within the home. Power-vented heaters run on combustion air provided from the home and require 110V. They save energy by using outdoor air that already has been expelled and is already hot or cold.
Not only do these devices meet Energy Star criteria, they often exceed it, ranking up to 15.5 percent more efficient than federal standards. Buyers of the power-vented water heater can expect to save as much as 14 percent annually in energy costs. Not only will you save money in energy cost, you will have cleaner air and your home will function more smoothly because of improved indoor air pressure.
These devices are flexible in their placement, and can be less expensive to install if they don’t have to conform to fitting into a chimney. When considering a power-vented water heater, weigh the benefit of maintaining a chimney versus purchasing a device with a side vent. Also, weigh the costs of these two methods, and when building a new home, consider not installing a chimney to save money if you opt for a heater that does not require one.
Conventional Water Heaters
How Do They Work?
Conventional, or traditional, water heaters store and preheat 30-50 gallons of water in a tank using air inside the room vented with a C-vent (metal). That preheated water goes through the side of your home and is used whenever someone showers, does the laundry, or washes dishes. The tank then refills to be reheated once again.
They are 60% energy efficient (10% less than power vented), so the flu gases are still hot because they weren't efficiently transferred into the water. Therefore, a venter motor is not required and conventional heaters can vent using the buoyancy effect. However, because of this, they are vulnerable to negative pressures created by dryer vents and bathroom and kitchen exhaust. These negative pressure can suck the flu gases back into the home rather than being vented out the chimney. This results in carbon monoxide. Power-vented and tankless water heaters do not have this problem.
Like power-vented water heaters, conventional heaters store water in a tank where it is kept warm until needed for use – so energy is being used to keep water heated even when you don’t need it. An example of this heater’s energy efficiency is that it will continue working even if you lose power to your house. But, since it uses the buoyancy effect, it’s more vulnerable to the negative pressures in your home and more likely to produce CO. And, conventional water heaters waste more gas than power vent water heaters. This is because conventional heaters use a pilot light that wastes more energy with an HSI.
Although conventional water heaters are less energy efficient than power-vented, they do cost less to install. So, it really comes down to how much bang you want to get for your buck. Remember that more energy efficient systems will save you money in the long run. Conventional water heaters heat and reheat water at a pre-set temperature, regardless of your water needs. This increases your utility bill – especially during the winter.
Now you better understand how the two systems work and can compare potential energy and cost savings. Make sure to purchase the most reliable system that best fits your requirements. Keep the air in your home safe and comfortable!
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