About tankless hot water heaters

So I just got out of interesting meeting with a potential client and the discussion came up about tankless hot water heaters and are they always the best solution to any given situation? Simple answer is NO! There never is “a” best solution to any given situation.

Water heater replacement just like anything in energy efficient construction and building should be looked at as a whole systems approach. Let’s say you have an old tank heater that needs to get replaced, here are the important things to consider:

1. Is it electric or gas?
2. If it is electric, is there a gas line nearby and will it be easy to install a vent pipe?
3. Where is is located? Is it more than 10 feet away from the source and does it serve sources that are located in different parts of the house?
4. If it is far from the source, can it be relocated to get it closer?
5. Are the sources spread out all over the house? (kitchen on one end, master bath on the other and guest bath over the garage….)

Answer those questions for yourself and you can come up with a good solution:

1. If it is gas, stick with gas and install a tankless gas heater
2. If your answer to question 2 is yes and yes, make the switch and install a gas heater
3. If your answer is yes, consider decentralizing your water heating system and install multiple smaller heaters to reduce your pipe runs from the heater to the source
4. If your current water heater location is pulling water from one end of the house to the other, consider moving the location of the water heater as close to the source as you can.
5. If your sources are spread out, you might be best served with 3-4 smaller electric heaters that can be installed under cabinets or in small closets. This is of course if your electrical service is adequate.

Just like anything else in a green building or remodeling project, you have to look at the whole picture – especially when it comes to the electric vs gas debate.. and btw – do not listen to your plumbers opinion, because it will always be gas. If you are remodeling your entire house, replacing plumbing, upgrading your electrical service and have the luxury of deciding exactly where your water heaters are going to be located, electric water heaters have some benefits:

1. Less expensive in initial purchase price
2. No gas lines to run
3. No exhaust venting and addtl wall/roof penetrations

Now the bad:

1. The good ones draw quite a bit of power – anywhere from 80-120 Amps – this means if you have 3 of them you need a quite sizable electrical service which can get costly if you’re not already upgrading your service anyway
2. Flow-rate – even the best electrical tankless hot water heaters have an inferior flow-rate to their gas counterparts which means you have to be very careful and thoughtful during the planning phase.

So when it comes time to replace your old water heater, you have to consider much more than just the actual piece of equipment. And that’s where we come in. EGC specializes in building energy efficient, comfortable and healthy homes. Your path to energy efficiency can start with replacing your water heater, but you have to do it right.

We are huge advocates of decentralized systems – gas or electric – because to us, the most efficient system is the one that wastes the least amount of water and has the least amount of heat loss from heater to source.  How many gallons of cold water do you run down the drain each morning before your water gets hot ??