This. I've put in a LOT of tankless systems - mostly gas-fired - and they do a great job of heating water very quickly, but a tankless heater by itself is not going to be a good system for a darkroom that requires large amounts of 70°-ish water unless it has a low-flow, low-heat capability. The amount of hot water that most faucets or tempering valves will draw in order to create the water temperatures that we want in a darkroom is almost non-existent, and that low of a flow at temperature is usually only reachable by having a system that maintains a reserve tank. Simply put, most tankless systems can't provide this small of an amount of heated water without 1) a reserve/holding tank and/or 2) a circulating pump in the mix, the price of which makes the entire system stupidly expensive and still not as functional as the "normal" way of heating water. Thus, I'll back up mopar_guy and suggest a conventional electric heater. Personally, I'd put in a 50-gallon because they're usually about the same price as a 40, and both of those are less expensive than the 30-gallon models in my neck of the woods...and come to think of it, that's exactly what I did.
Originally Posted by mopar_guy
The local HVAC dealer says the new tankless are the most efficient available. No heating water all day for the few bits of time you use it. When we were in Portugal we had propane fire tankless. Could set the temp and flow at the heater. Grease pencil marks for each family members preferred shower temp. For my 54 degree F ground water temp it would take an electric tankless about 2 KW an hour to provide 68 degree F darkroom water. Can you say 20 amp breaker. (for a gallon a minute flow). If you can go to a low flow then tankless electric is the easy on the budget direction.
What are you going to do with the hot water? Why not buy a Jobo instead of a water heater. The Jobo has the heater built in. In my darkroom I use tempered water only to fill the Jobo (convenience) and to mix Dektol (as mentioned above).
Thanks Sundowner and all you others who've provided feedback. This is exactly the sort of experienced based information I knew would be forthcoming from this diverse group of folks.
Originally Posted by Sundowner
I will go with a tank unit, power is already there. but I'm afraid I'll have to go with a 20 gallon based on size constraints. (it's that or just cold water...)
I already have a Jobo and it does a fine job of tempering my film processing liquids, but for print washing and some of the alt processes I want larger quantities of running, tempered water available.
Originally Posted by ic-racer
As I have an opportunity to build (though on a tighter than I'd wish for budget, but that's what retirement gets me) my first designed-by-me darkroom, I want to have hot water available when I need it.
Having spent the money to have drainage and water run out back to the garage, and agreement from the wife to use (a bit less than) half of the space, a hot water tank is not a big stretch financially. I expect this to be the last (and first) time I get to put a darkroom together with "wants" and maybe even a few "nice-to-haves*" instead of making do with re-tasking available spaces other people's ideas of darkrooms.
* the Jobo and an Expert drum was one of the biggest "nice-to-haves" I ever got to have in my darkroom.
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You probably don't need much more than 20 gallons since the hot water demands are so low. As you're using electrical power instead of gas I would DEFINITELY go with a conventional heater; the increased initial price of the electric heaters takes a LONG time to get paid back...especially when you're not using the unit all that much.
Originally Posted by Dave Swinnard
In BC, we are blessed with relatively cheap electricity, but I would go with an electrically heated tank anyways, because it frees you from most venting concerns.
Originally Posted by Sundowner
And Dave, don't forget to get a really well insulated tank - for those frigid Parksville winters .
(For the uninformed, Parksville has the highest average winter temperature in Canada - the retirees absolutely flock there!)
“Photography is a complex and fluid medium, and its many factors are not applied in simple sequence. Rather, the process may be likened to the art of the juggler in keeping many balls in the air at one time!”
Ansel Adams, from the introduction to The Negative - The New Ansel Adams Photography Series / Book 2
Originally Posted by MattKing
Hydro prices on the Island are NOT relatively cheap compared to the mainland. Our first heating bill last fall (all electric) for a house half the size of the Coquitlam one was more than double the Coquitlam one. We had gas run in ($$) for a fireplace last February and our winter bills dropped significantly.
Retirees, yup. Only Qualicum Beach (10 minutes farther up the road) has an older per-capita population in Canada.
You might want to consider longevity when comparing tank to tankless - and not the numbers in the sales brochures, but some independent reports. If you intend to stay in that house for a while, it may pay to go with something that has a longer life.
Now for my personal bias:
- I'd go for a tank heater with a very high efficiency rating. If it's only for darkroom work, you can also set the heat low as you won't need it as hot as you would in the kitchen or bathroom.
- I don't trust the "instant" heaters - though I'm thinking whole-house, not something as specific as you are. I've read the data, and used a few in action, and was not particularly impressed.
- Personally, I'd run a natural gas line to the garage (if your house has it) and use a water tank.
On the other hand, a tank may not be great if it's not constantly in use. Setting for long periods may somehow affect the quality of the water; chlorine does dissipate with time (I'm thinking of something growing in the tank, though don't know how likely it would be).
You don't want legionella growing in your tank. The recommendations I have seen say the tank should be set to 140F/60C to kill legionella. Then use a tempering valve to reduce the temperature to the hot water line down to 120F/48C. Doing this will also let you stretch the amount of hot water you get from the small tank size you need to fit your darkroom.
Originally Posted by Truzi