Hot tub heater size - 250 vs. 400 btu?
rockybird
12 years ago
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Hot Tub Spa Ratings
12 years agopoolguynj
12 years agoRelated Discussions
Tankless water heater sizing
Comments (16)My main uncertainty at this point is what to use as the intake water temperature. The plumber that came today said I could figure 60 degrees F for Sacramento in winter which sounds high to me. I was expecting something between 40 and 50 degrees - our pond gets to 40 degrees in the winter but perhaps the water pipes underground don't get quite as cold as that. If winter water temp was 55 or higher, then 105 takes a 50 degree rise. The Noritz 751 would supply 6.7 GPM at that temp rise which sounds like plenty for this situation. On the other hand, if intake water temp goes down to 40, the temp rise would be 65; the Noritz would only supply 5.2 GPM which seems marginal to me (though its enough for the two showers). The alterantive would be to use the Noritz 841 but that only increases the output at 65 rise to 5.8 and it costs a lot more - list price is about $1K more but I haven't gotten price quotes yet. Also haven't seen prices on the other brands yet. The Noritz 841 is condensing, but since we only need a straight vent run of about 10 feet, I doubt that PVC will save us much over stainless. In this case, there are no appliances drawing from this water heater. There is another water heater that services the kitchen, utility room and other baths. The big tub just has a regular tub spout that does about 5 GPM but the tub is tiled so it has a lot of heat mass so filling it one uses mainly hot water to end up with a hot bath after the tile has taken heat out of the water. If we run the water heater at 105 or 110 degrees, the tub would probably be filled with just hot water going in....See MorePaloma versus other tankless hot water heaters
Comments (18)We have a Noritz feeding 2 bathrooms only. Kept the tank heater for the kitchen and laundry, but it was too far away for regular bathroom use. We've been using it for a little over a year now without problems. It's mounted outside, which eliminated some of the cost associated with vent piping. But not the cost of increasing the gas line. I looked at Noritz and Takagi mainly. Think I chose Noritz due to slightly bigger burner or flowrate- it's been a while so the memory is a touch fuzzy. I've debated w/ one of the pro plumbers here about this. I can't run everything that's hooked up to the tankles w/o noticing reduced flow at the outlets (that's 3 lavs, two tub fillers, and 2 showerheads). The pro thought the heater was actually limiting water flow to try to meet its setpoint. I thought maybe my incoming cold water line is too small or that their isn't a direct enough path in terms of pressure drop to the heater inlet to get the flow at the fixtures with everything turned on. And there's a valve in the crawlspace that I can open and run hot water from the non-electrified tank heater during a power outage. Rinnais appear to only be available via certified dealers. In our case that would've meant paying someone separate from the plumbing sub who was working on the project anyway. I could buy the Noritz and get it installed by our plumber, which I think saved money over the Rinnai route (even with the $500 incentives the gas co was offering on Rinnai only at the time)....See MoreHeater vs. heat pump, the great debate! At least in our house.
Comments (8)Here's my 2 cents on the subject. We had a gas heater for our pool when we lived in Southern CA and now have an electric heat pump in Phoenix. In CA, the gas heater was the way to go. Gas is less expensive in CA. It took less time to heat the pool with a gas heater. In Phoenix, we have the heat pump. We decided on the heat pump because we don't have a spa and only wanted to extend the season a month or so each way. So far (two years) it's worked out just great. In March we set the temp to 88 degrees and when the pool is on in the evening (lower rates) the heat pump is on. Yes, I know...everyone will say that the heat pumps only works with the sun, however we've had great results running it at night. In the morning the pool is ready to swim. Now...we do have to start this process about 3 days before we want to swim. So when the weatherman tells us that it will start to become warm, we start the heat pump. It costs very little to run if you run it during the evening hours. We're very happy with the heat pump. Now, if we had a spa, that would be a different story. We would have to go with gas....See MoreElectric vs Gas Tankless Water Heaters
Comments (29)Wow, thanks for all the good input. I didn't intend it to become a debate about solar, but found that interesting as well. I'm not familiar with the lease program that is mentioned. I'm looking to have an array installed that will be owned completely by me. I can get a 20kw system installed for about $60,000. There is a new Duke Energy program offering $1 rebate for each kw installed, so subtract $20,000. Then there are 55% state and federal tax credits, reducing the investment further to $18,000. The system should generate about $2,500 in energy per year (assuming 9 cents per kwh), resulting in about a 7 year payback. There is also potentially a benefit I can derive from depreciating the asset, but am not sure that is allowed, so need to check with my tax expert. I think the main different between now and before is the $1 Duke rebate. Without that, I agree the payback period would be too long (about 11 years), but a 7 year payback seems reasonable to me. There is always the possibility of repair costs in the first 7 years which could lengthen the period a bit, but the warranties on the panels at least are much longer than that. In any case, I think it is a worth a try. With regard to the water heater question, I agree that two heat pump units might be too many, as the one in the basement might be idle for long times, so am not considering doing 1 heat pump (for the upstairs which will get used daily, but shouldn't use more than 80 gallons per hour as there is only 1 shower), and then a gas powered tankless for the basement. We have natural gas that will be already piped to the house for the stove/grille. Any other thoughts or suggestions are welcome, thanks for the lively debate!...See Morerockybird
12 years agopoolguynj
12 years agoRack Etear
12 years agorockybird
12 years agoAlberto
11 months ago
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