Anyone using a UPS for a tankless water heater?

Electric hot water? I'm sure the draw is more than a few hundred watts.

If gas, then you only likely need to run the electronics and a UPS would work, but keep in mind UPS batteries don't like regular deep discharging. I'd be looking at a small generator instead.

The OP is talking gas (being that gas is more common and talks about a vent)...If it was electric it would take a huge UPS or large generator

We don't have one on ours (we have generators) but I suppose you could put it on a UPS, particularly for occasional short term use. For longer periods you'll probably want a generator. They don't take too much power, usually some electronics and combustion blower. Look up it's rated power draw and size the UPS accordingly. If you can disable the de-icing temporarily would be helpful.

Yeah, the tankless is natural gas.

Actually the house is wired for a backup generator, and the previous owners actually left their gas generator here. Apparently it's hooked up through a daughter panel with a 30 amp breaker, such that if the generator breaker is on, the main breaker to that daughter panel gets turned off, and vice versa. The daughter panel supplies some stuff in the kitchen, like the refrigerator. I think it used to supply the over-the-range microwave/range hood as well, but that's since be removed and replaced with a high cfm range hood.

However, I've never actually even tried to start the generator in the 5 years I've been here, so who knows if it still works. I think I might have to give it a shot one of these days, but I've never used one of these. The thing is quite large, and sits in the garden shed. After 5 years of non-usage I might have to get it serviced. Hopefully it's not full of gas gumming up the works.

However, for the tankless, the instructions say it only needs 220 Watts max in the winter, and the standby is 2 watts. I'm thinking a 1000VA UPS should suffice, if just to give us enough time to finish off quick showers (longer than 2 minutes), etc.

P.S. Both my router and my DSL model and all my main Ethernet switches in the house are on UPSes. After the power outtage, we still had internet access for about 45 minutes with regular sized home UPSes.

Sorry, a bit off topic, is it common to install a natural gas powered back up system ? I think it us great idea than installing multiple UPS or power generator for selected appliciances or electronics. Does anyone know how much for installing a system like that ?

rdx wrote: ↑Sorry, a bit off topic, is it common to install a natural gas powered back up system ? I think it us great idea than installing multiple UPS or power generator for selected appliciances or electronics. Does anyone know how much for installing a system like that ?

Good question, but suggest you start a new topic rather than go off-topic in this thread. Better for you and subsequent readers. I've recently looked into it and would be happy to tell you what I know.

JWL wrote: ↑Good question, but suggest you start a new topic rather than go off-topic in this thread. Better for you and subsequent readers. I've recently looked into it and would be happy to tell you what I know.

Yes, agree. Here it is natural-gas-backup-generator-1223953/#post15303519

Thanks in advance for any advice

I turned on the hot water for the bathtub full blast, along with two sinks. The power usage spiked up to just below 80 Watts. I was a little surprised the power usage was constant, not just for the initial spark. Plus, a couple hundred Watts would be needed for the vent heater. So, I'm thinking probably to get any sort of decent usage out of a UPS, a 1500+ VA small business type model as a minimum would be advisable. That's pretty beefy, and a bit pricy at around $180 to $220+. I will wait until I find one on sale and I'll get one. I think I've seen them drop to about 2/3rds that price.

BTW, standby power usage is only 2 Watts.

EugW wrote: ↑However, for the tankless, the instructions say it only needs 220 Watts max in the winter, and the standby is 2 watts. I'm thinking a 1000VA UPS should suffice, if just to give us enough time to finish off quick showers (longer than 2 minutes), etc.

EugW wrote: ↑I turned on the hot water for the bathtub full blast, along with two sinks. The power usage spiked up to just below 80 Watts. I was a little surprised the power usage was constant, not just for the initial spark. Plus, a couple hundred Watts would be needed for the vent heater. So, I'm thinking probably to get any sort of decent usage out of a UPS, a 1500+ VA small business type model as a minimum would be advisable. That's pretty beefy, and a bit pricy at around $180 to $220+. I will wait until I find one on sale and I'll get one. I think I've seen them drop to about 2/3rds that price.

OK close enough. There is a Hot Deals thread for a 1350VA model at $99.99. Great price It's a simulated sine wave model, but that's good enough for now, esp. since it's simply AC pass through when the battery isn't in use. Once a pure sine wave 1500VA model shows up for cheap, I'll buy it, and then repurpose this 1350VA one for something else.

EugW wrote: ↑However, for the tankless, the instructions say it only needs 220 Watts max in the winter

My tankless water heater (designed for both propane and NG) runs on exactly one D battery, which is used only for the spark AFAIK.
I have had the same battery there for at least the past year.

Why does yours use so much more power than mine?

Just buy a generator from Costco next time they go on sale. Last year I got a 4000w for $279. 4000w can power a lot of stuff in a blackout, including your fridge and freezer.

Ron wrote: ↑My tankless water heater (designed for both propane and NG) runs on exactly one D battery, which is used only for the spark AFAIK.
I have had the same battery there for at least the past year.

Why does yours use so much more power than mine?

What's the model? Is it not direct vent (combustion fan)?

brunes wrote: ↑Just buy a generator from Costco next time they go on sale. Last year I got a 4000w for $279. 4000w can power a lot of stuff in a blackout, including your fridge and freezer.

As I mentioned above, I actually have a generator. I just have never used it.

The power may go out for say a few minutes, to a few hours max. In that context I can't be bothered to start it up.

That said, maybe I'll start it up next year just to see if it still works. I figure it'd cost me >$100 to get it tuned up though, since they'd likely have to come to the house to do it.

sprdave wrote: ↑What's the model? Is it not direct vent (combustion fan)?

Oh, that's probably why. Mine doesn't have a fan - it just connects to the building's ventilation shaft.
It's installed in Florida, probably different standards than in colder climates.

EugW wrote: ↑OK close enough. There is a Hot Deals thread for a 1350VA model at $99.99. Great price It's a simulated sine wave model, but that's good enough for now, esp. since it's simply AC pass through when the battery isn't in use. Once a pure sine wave 1500VA model shows up for cheap, I'll buy it, and then repurpose this 1350VA one for something else.

Some people said Costco has the APC 1500va for $146 regular price

Keigotw wrote: ↑Some people said Costco has the APC 1500va for $146 regular price

Thanks, if it's the BR1500G then that's a good regular price, as it normally goes for around $180-220. However, it's still a simulated sine wave, relatively low battery capacity model. So, in terms of bang for the buck, the Cyberpower 1350VA model at $104.99 is a better deal. Then again, the APC has a faster recharge time, and supports the addition of an external battery pack. However, that would bring the total price to over $300. At that price, you might be better going with a higher end medium business model with a bigger built-in battery size and sine wave output.

The server 1000VA model is rated for 300 W for 25 mins, and supports true sine wave output. It's probably a bit less real world.
The home 1500VA model is rated for 300 W for 21 mins, but has simulated sine wave output. It's probably a bit less real world.

I don't know what duration the simulated sine wave 1350VA Cyberpower is rated for at 300 Watts, but I'd guess somewhere in the range of 15 minutes real world.

FWIW, this review has the simulated sine wave 1350VA Cyberpower lasting 25 minutes at 180ish Watts.

I have a Rheem RTGH-95DVLN 9.5 GPM Indoor Direct Vent Tankless Natural Gas Water Heater and determined that it's recommended power backup unit 'HUGO' had specs 500VA/350W Pure Sine Wave output.

An APC BN650M1-CA Back-UPS 650VA/360W from Costco is providing me with aprox 7 hrs of power during outage. I tested and confirmed this by pulling it's power after allowing it to charge for 24 hrs. It's not 'Pure Sine Wave' but does the trick for a reasonable cost. I can't afford going solar which would be the better solution. You can stretch out the 7 hrs by powering it off when not needed. Perhaps having a 2nd UPS (keeping one unit powered up and turned off) to swap out whenever you change your furnace air filters would be advisable.

If your provider ever sends a technician, perhaps disconnect and leave these out of site so they don't have an excuse to void any warranty.

EugW wrote: ↑ Yeah, the tankless is natural gas. Actually the house is wired for a backup generator, and the previous owners actually left their gas generator here...

Since the house is already setup for a backup generator, wouldn’t it be better idea instead to see how much effort is required to get the system working? It might be as easy as just adding gas