Indirect vs. tankless vs. electric

John_34

For a family of 6, generally which is the most efficient?

Dave_40

Indirect

I would say. Maybe tankless, but you would need a big one, and don't plan on multiple showers at once. My $.02

DaveGateway

Those high GPM tankless

WH are over $1K, just for the unit. An electric tank will probably require at least 100 to 120 gal just to cover your recovery time. Go indirect.

Rookie_3

Electric takes too long to recover and cost far too much to run. Cheapest to install but you'll pay in the long run.
I'd go Indirect over tankless every time. I'm sure you can get different opinions but I like a sperate zoned indirect set up cold start...............BB

Constantin

I vote for indirect.

... it gives your boiler a good chance to cycle for a while, minimizing stack and standby losses.

I have yet to see a tankless coil that has the same rating as the burners in a boiler.... Thus, whatever ΔBTU between the output rating and the coil rating will go up the flue, doing you no good other than burning a hole in your wallet.

Electric water heaters are not efficient. They turn a very-inefficiently produced commodity back into heat. Hence their high operational costs. Plus, they take forever to recuperate.

Have you considered a direct-vent gas water heater? Their AFUE ratings may not be great but they are dirt simple and require no chimney or power.

J.C.A._3

I'll agree with BB

With 1 acception.No cold start. I would pay the extra dough for a control that maintains at least some boiler temp. A priority control helps but if it's set at the same temp as the desired domestic temp. a maintenance control gives the indirect a bit of a headstart on doing it's job.It also keeps the boiler from fighting itself.

When the indirects started taking off, we found that cold starting was kind of self defeatist. If the indirect was sitting at 120° and the boiler was cold, on a call, the circulated water would actually start heating the boiler water, before it started heating the tank water,throwing the actual recuperation time off a bit.The recoup time of the indirect suffered until the boiler temp. surpassed the water being passed through it.Does this make any sense? Keeping the boiler at even a slightly elevated temp. gives it a kick and also keeps the chimney flowing(if used) by keeping it warm. Tests have showed that the fuel used to keep a boiler warm isn't too much more than trying to run cold start until you get into very low mass units. Havimg serviced multitudes of units over the years I will also say that something kept warm is alot easier to service. Less time for a service =less $ in the long run. I've always considered this a vicious circle but will stick to my guns . Maintenaing some temp. will save you some $ in the long run. Chris