That tank is too small, for the house and number of occupants. We have a 60 or 70 (can't remember right now) and a 2 1/2 bath 3800 sf house. Two occupants, someday four.

I decided against the body shower nozzles because of the amount of water they would go through (we are on well and septic). Add up the gallons per minute of the nozzles and the shower heads, whatever will be used at once. They figure the length of shower you might take. Tex minutes minimum. You will see how much water you will go through.

How big is the tub? When we were sizing the plumbing system one of the things the plumber asked was whether I was getting a Jacuzzi/soaking tub. If we had, he would have gone bigger (we have a clawfoot instead, doesn't use as much water).

We have a 65 gal tank (propane) - 2 adults, 1 1/2 baths. It fills up our soaking tub no problem.

I think your tank is probably half the size it needs to be - fortunately hot water tanks aren't horrendeously expensive.

It is not all about the size in gallons; it is about the BTU's. I have only a 50 gallon WH that I use to heat my entire home plus the usual demands of showers, sinks, dishwashers, etc. It NEVER runs out of hot water because of it's BTU rating (199,000 I think) and efficiency level (96%+). Sunday morning it was -34°F outside not including the wind chill!

Of course my water heater was about $4k; not the $500 variety you see at the home stores...

Hi Buzzsaw,

This is not really completely related to the thread but I see you mention wind chill as if to suggest that wind chill influences the performance of the water heater.

My wife and I recently discussed this topic and she maintains that if the wind chill is lower it will cause the thermostat to call for more heat from the furnace or cause the heater in the tank to fire. I thought wind chill was more of a qualitative phenomenon that would affect humans and animals but not inanimate objects like a house for instance which would only really respond to ambient temperature.

Can you explain how wind chill affects heating systems please? My wife suggests that the wind draws the heated air that escapes the house and replaces it with colder air, therby lowering the immediate ambient temperature that surrounds the house. Is this notion correct?

.

Wind chill on humans . . . wind chill on inanimate objects. Similar but different things.

If it's 0 degrees . . . ANY inanimate object; will eventually cool down to that temperature. How FAST that happens is affected by the wind. The more wind blowing; the faster the heat is removed, the more quickly it will cool down. But it can NEVER get below the air temp of 0.

Animate objects: We have a body temp to maintain. The absolute air temp will make us feel "cold". When the wind is blowing; the air "feels" colder because of the RATE at which heat is being removed from us. Also; animate objects evaporate moisture off our skins . . the more air movement; the more evaporation; the colder we feel. Since the wind is removing heat at a faster rate than if it were still air; we FEEL as though it's colder. That's why the wind chill can be lower than the still air temp => and affect us; but not inanimate objects.

As far as "wind chill" and affecting the thermostat cycling; well, yes. The wind is causing your house to lose heat to the surrounding air faster than if the air were still. As far as triggering a water heater more; I'd say bolderdash to that . . . but definite yes to "wind chill" impacting your thermostat. Your place cools down quicker as sensed by the thermostat. Your water heater does not see any direct impact from the air outside . . it's in a fixed environment.

Bob

Actually what buzzsaw said was partially true. The wind chill factor is not really relevant in terms of how it affects the water heater outside of its indirect ability to wisk more heat away from the house.

However, it is true that its not all about size in gallons. We tend to think that if you use a traditional water heater, its all about size in gallons, and when its on-demand, its all about gpm. It's actually a function of first hour delivery, recovery capacity and gpm. Gauging from what buzzsaw has, he probably has one of the ultra efficient sealed/submerged combustible gas water heaters. The 50g sizes usually can take up to 200k btu, the 100gallon and larger ones can take 200, 250, 350, 450k btu's. So, not only does the water heater have the capacity to keep up with hot water demands continuously (like 5 gpm), but it also has immediate storage for delivery.

These units have the best of both worlds - they can keep up with constant delivery at moderate flows (even more than tankless), they are 95+% efficient and have very large first hour recovery. Their only drawback is that they run from 4k-6K in cost (about 3x a tankless). They gain their efficiencies by having a submerged combustion chamber that spirals the heat through the water heater. By the time the gas exhausts it is almost cool to the touch. Compared to regular gas heaters (80%) and tankless (about 65-75%) they are amazingly efficient.

But yes, it isn't always a function of tank size, recovery capacity can also be used to factor it in, its just that recovery capacity on standard grade gas/electric water heaters isn't much to speak ok that it matters.

The wind chill had nothing to do w/ WH performance. I didn't mean to confuse anyone w/ the wind chill comment. I was merely 'bragging' how cold it is outside here and that my WH needs to throw out a lot of heat to heat my house. It is just that whenever I tell someone a temp that low they always respond with "that's the wind chill temp?". I 'thought' I would head off the question beforehand, but it didn't work that way.

Yes, the startup and recovery time of my water heater is amazing. I remember filling it up the first time w/ 50 gallons of 40°F water. It took that to 130°F in all of about 5 minutes. Sweet!

buzzsaw, my only comment is that instead of the 50, you probably should have gotten the 100. It has the exact same footprint but only a bit taller. Most times when the capacity is larger the jacket diameter also increases, but these ultra high efficiency ones dont really. Not only does it give you 100 gallons, but it also adds a few more percentage points in efficiency (larger spiral pipes).

What brand is your unit ? If you said 199, my guess is that you have a Bradford ef series unit, or a rebadged BW unit (like Bock or something else). Might be wrong, but just a guess :-).

Hi Anthem,

Here is the link to my WH. It runs so efficient it vents with PVC. 100 gallon may have been nice to minimize starts and stops. For me, actually height would have mattered, but not diameter. I don't know if this one by American is re-branded or not.

Here is a link that might be useful: Polaris 50 Gallon Water Heater

I've got the AO Smith 50 gal Vertex condensing water heater. So far, I'm underwhelmed. It can't keep up when I fill the bathtub. In reading the spec sheet I see they guarantee a continuous 3gpm. I'm guessing my tub filler draws more than that wide open. This was a $1400 water heater so it's not quite in the same league as buzzsaw's.

This bugger has a side loop feature & I hoped to use it as the source for my future floor warming radiant system. Now I'm wondering if it'll have the capacity I need...

Here is a link that might be useful: AO Smith Vertex

We got two 85 Gallon Marathon Heaters which are guaranteed for life. We have six bathrooms (two of which are 1/2 baths) and a whirlpool tub. We paid about $600 dollars apiece, and they are designed to work with our geothermal heating system (don't ask me for technical info - I don't really get it), but as I understand they use the excess heat to heat the water heaters. They aren't installed yet, so I can't report on how they are doing, but if anyone is interested, I'll let you know when we start using them.

beachgirlok, can you report on how well your heat recovery system with the Marathons are working? I've just purchased some Water Furnace Geo Thermal units and I'm considering Marathon for the hot water heaters.

Our contractor was going to use a 40gal, but we optioned up to an 80gal (electric). It is still the budget type appliance. We had a large garden tub that I wanted to be hot! In our last house, the garden tub could only get lukewarm due to the 40gal WH.

The builder did charge $350 for the upsize, which was a little stiff I thought.

We're building a 2400sf home with 2.5 bathrooms. We went with two 40gal tanks in tandem. The master will have a large Kohler air tub.