To figure out how many BTUs you need for your indirect water heater, you need to consider your boiler and the peak load demand of your household.
There are many types of water heaters available on the market and your household will determine which is suitable for you and your needs.
Indirect water heaters are one of the most energy-efficient types. However, they need to be paired with a boiler that has the correct BTU to pair with the water heater and have it work effectively.
Different types of water heaters
Over the years, as architectural and design styles and technologies have changed, manufacturers have also developed varying kinds of water heaters to fit into different kinds of homes and to meet household needs.
This includes traditional storage tank water heaters, which have a tank of hot water ready at any moment, tankless water heaters, which heat your water as it flows through the unit, heat pumps, which work similarly to how an air conditioner works, solar heaters, which do not require any gas or electricity to heat up water, and indirect water heaters, which use your space heating system to heat your water and then distributes the hot water through your home.
How many BTUs to add for indirect water heater
Indirect water heaters are popular, especially in homes that already have a furnace or boiler installed, because they are extremely efficient.
This efficiency attracts many homeowners to the idea of using an indirect water heater instead of any other kind, because your water heater can be one of the appliances in your home that uses the most electricity to run.
However, it can be quite difficult to determine the size of the indirect water heater that you will need for your home, as well as the size that your boiler should be to provide enough input BTUs for the indirect water heater to function properly.
Terms such as heat loss, water flow rate, and more can be incredibly confusing to understand. On average, indirect water heaters require that your boiler has at least 30 000 BTU capacity in order to heat the water sufficiently.
It is, however, important that you consider the manufacturer’s requirements for your specific indirect water heater and its boiler BTU requirement, or that you rely on a professional to do the calculations for you.
There are also a few factors that you need to consider when you are deciding on the most appropriate indirect water heater for your home. It is also vital that you consider whether an indirect water heater system is really the best option for your home.
What to consider when deciding on the size of your indirect water heater
When you are considering what size indirect water heater to get for your household, the BTU of your boiler should not be your only concern.
You should also take into account the peak load demand of your household, by looking at factors like the number of people in the home, their hot water usage or requirements, and the duration of this hot water requirement.
You or a professional should then search for indirect water heater models that meet this demand and that will ensure that you have hot water in the house when you need it and for as long as you need it.
During this process, it may be helpful for different members of the household to track and time their hot water usage to get a realistic data set and determine this demand accurately.
The pros and cons of indirect water heaters
The most obvious benefits of having an indirect water heater system is that you will have on-demand hot water, while saving on your electricity bill in the long term.
As long as your indirect water heater is appropriately sized for your home, you should have hot water from all your fixtures instantaneously.
The only drawback of indirect water heater systems is that they do require that you also have a boiler installed and they need a storage tank.
When you should and should not install an indirect water heater
Indirect water heaters work well in homes that already have boilers for space heating purposes.
If your home has a forced air HVAC system, the additional costs of installing a boiler, ducts, and vents before you even get to the cost of the indirect water heater itself, means that it simply will not be a viable choice.
Indirect water heaters are also not the best choice for a home that only requires a small amount of hot water at a time, as you will be wasting energy to keep the full storage tank warm when this is unnecessary.