back to blog

The basics about hot water heaters types, parts, and how they work

It’s large, it can make odd noises, and — somehow, in some way — it creates hot water. Homeowners could be forgiven if this is the most knowledge they have about their home’s hot water heater. Buying a home does not automatically transfer over the information for how every appliance and fixture works, nor is it necessarily required. But being informed about the basics of how hot water heaters operate, which types exist, and which parts are most important can provide homeowners with greater peace of mind when trying to figure if what’s happening with their heater is normal, or an issue worth exploring.  

The Types of Hot Water Heaters

There are generally two major types of water heaters for homes: the classic, traditional heaters with large tanks referred to as “tank” water heaters, and the smaller, boxier variety known as “tankless” water heaters. 

True to their name, tank water heaters operate by heating water using either electricity or gas, then storing gallons of hot water within the large tank attachment. Cold water enters the unit from below the tank and is heated either by a gas flame or electrical elements within the tank, depending on the heating method. If gas is used to heat the water, then exhaust fumes are funneled out of the unit either via an internal flue, or a dedicated exhaust pipe, that leads to the outside.

The temperature inside the tank is regulated using an attached thermostat and control valve, and the pressure in the tank is maintained at a precise level, with a pressure-relief valve attached to release excess pressure. The water stays in the tank until a hot water faucet is turned on, piping hot water out of the top of the tank, and automatically triggering the tank to begin refilling again, restarting the heating cycle.

Tank water heaters are available in anywhere from 20- to 80-gallon tanks, have lower upfront costs than tankless water heaters, but use energy throughout the day and night to maintain the temperature within the tank; and if the tank is not full, it can take time for the water to come up to temperature. In general, electric models are slightly cheaper than gas models, and both have about the same lifespan, about 8–15 years depending on the model. 

How about a Tankless Water Heater?

Tankless water heaters are generally smaller than their tank counterparts and attach directly to a wall within the home. Also called “on-demand” or “instantaneous” water heaters, these units do not store water within them. Instead, the tankless water heater works by only drawing water when a faucet is turned on. As water enters the unit, a flow sensor kicks on to activate the heating element — again, either gas or electric-powered — which heats the water as it passes over the heat exchanger. This allows hot water to exit the unit only when hot water is needed. Similar to tank units, tankless water heaters that utilize gas have a dedicated exhaust pipe to funnel out fume from heating.   

Because tankless heaters don’t store water, and only use hot water when activated, they are generally more energy-efficient than tank heaters. Lasting up to 20 years, tankless waters are a bit more pricey than tank units. Additionally, some units are said to be less effective at heating water than tank units, but they provide hot water more consistently. 

Which Unit is the Right Unit?

Both tank and tankless water heaters have benefits and drawbacks, and both can provide hot water for homes of any size. When researching which unit is best for your home, take into consideration the upfront cost of the unit, which unit better fits the size of your home (as choosing the biggest unit is not always best), and which appliances will be attached to the unit. 

If you have any questions about finding the right type of water heater, or if you’re thinking about switching out the current unit in your home, reach out to professionals at Duane Blanton Family Home Services. Experienced and knowledgeable, the plumbing experts at Duane Blanton will be able to guide homeowners through finding exactly which hot water will best suit your unique needs. Give the plumbing pros at Duane Blanton Family Home Services a call today, at (815) 781-2567, or use their online scheduling portal to conveniently schedule right from your phone or desktop browser!


Dave, Mike & Matt were our guys from estimate to installation. All of our workers did amazing work. They were on time, worked efficiently, explained…

Britni S.

Mike and Tim were a great help with my water heater issue. They went over what the problem was, what the solutions were, and did…

Eric B.

Very friendly phone operators. Professional workers. Arrived very quickly and it wasn’t even a serious emergency. Very good communication throughout the whole process with every…

Danielle D.

These guys are WONDERFUL! Especially if you have an older home and old pipes. We have the service package that covers pipes, boiler (heating) and…

Lisa M.

We had water coming through our kitchen ceiling and someone was able to come out same day and identify the problem. Michael B and Aaron…

Meaghan D.