Choosing the right size water heater is important for comfort, performance and avoiding unnecessary equipment costs.
A water heater that cannot keep up with household demand may leave people running out of hot water. At the same time, simply choosing the largest available system is not necessarily the best solution.
Proper sizing starts with understanding how your household actually uses hot water.
Household Size Is a Starting Point
The number of people living in the home provides useful information, but it does not tell the entire story.
Two households with four people can have very different hot-water requirements.
One may rarely use several hot-water fixtures at the same time. Another may have multiple showers operating while laundry and dishes are being washed.
This is why water heaters should be selected based on expected usage rather than household size alone.
Consider When You Use Hot Water
Peak demand is particularly important.
Think about the busiest hot-water period in your home.
It might involve:
- Morning showers
- Multiple bathrooms
- Dishwasher use
- Laundry
- Kitchen use
- Baths
- Several activities occurring together
The water-heating system needs to perform during these periods, not just when one faucet is running.
Sizing a Storage-Tank Water Heater
Storage water heaters keep a quantity of heated water available inside the tank.
Tank capacity is important, but it is not the only consideration.
How quickly the system can heat replacement water also affects how well it handles household demand.
This means choosing a conventional water heater should involve more than simply matching the tank size of the old unit.
Sizing a Tankless Water Heater
Tankless systems are sized differently.
Because they heat water as it flows through the unit, expected simultaneous flow is an important consideration.
The system needs to be capable of meeting the household’s required hot-water flow while producing the necessary temperature increase.
This is why tankless sizing should be based on actual operating conditions rather than simply choosing a unit advertised for a particular number of people.
Think About Your Fixtures
The number and type of plumbing fixtures can affect hot-water demand.
Consider whether the home contains:
- Multiple showers
- Large tubs
- Several bathrooms
- High-flow fixtures
- Hot-water appliances
A renovated home may also have different requirements from when the existing water heater was originally installed.
Consider Future Changes
If you are already replacing your water heater, think about whether your household is likely to change.
For example:
- Is your family growing?
- Are you adding another bathroom?
- Are you renovating?
- Will more people be living in the home?
- Are you changing fixtures?
Sizing only for today’s minimum requirements may not make sense if a significant change is already planned.
Bigger Is Not Automatically Better
It may seem logical to solve hot-water problems by simply buying a larger water heater.
But proper sizing is more useful than automatically oversizing.
Equipment selection should consider household demand, available utilities, installation requirements and the type of system being installed.
The goal is to choose equipment suited to the property and its occupants.
What If Your Current Water Heater Is Too Small?
If your existing water heater regularly runs out of hot water, first determine why.
The problem may be capacity, but it could also involve equipment that is not operating correctly.
If you’re experiencing a sudden change rather than a problem that has always existed, our article on why your water heater may not be producing enough hot water explains several possible causes.
Tank or Tankless?
Sizing also depends on which type of system you choose.
A conventional storage water heater and a tankless unit deliver hot water differently, so they should not be compared using tank capacity alone.
The right choice depends on the home, expected demand, existing utilities and installation requirements.
Water Heater Installation in Kamloops
Before purchasing equipment, having the home’s requirements assessed can help prevent choosing a system that is poorly matched to the household.
Stillwater Plumbing & Heating provides water heater installation in Kamloops and can evaluate the home’s hot-water requirements when replacing or installing a system.
Call (250) 819-8247 to discuss your water-heating needs.
Frequently Asked Questions
It depends on household hot-water demand, the type of water heater and how many fixtures may require hot water at the same time.
No. The number of occupants is useful, but actual usage patterns and peak demand are also important.
Not necessarily. Proper sizing is preferable to simply choosing the largest system available.
Tankless systems are selected partly according to expected hot-water flow and the temperature increase the equipment needs to provide.
Not automatically. Replacement is a good opportunity to reassess whether the existing system is properly sized for your current and expected hot-water requirements.
Signs Your Water Heater Needs to Be Replaced
