Which Gas Hot Water Heater?

cubicacres

Our small 5 unit apartment building (9 people total, 5 bathrooms) has 2 chimney-vented gas hot water heaters (one 40 gallon Hotpoint 40K BTU 55gal 1st Hr capacity installed in 2013 & one 1993 Vanguard 50 gallon 40K BTU 74gal 1st hour capacity that's leaking on the drain).

We're thinking we could replace the 24 year old Vanguard heater with a new 40 gallon 60-70 1st hour capacity one using the same chimney venting to avoid drilling a new hole through the brick wall for power-venting.

We saw Lowe's & Home Depot have some A.O.Smith & Rheem units with the capacities we're considering. Any thoughts on deciding between similar models/brands? We're wondering if the higher efficiency models are worth the higher price.

EBEBRATT-Ed

as far as efficiency you need to look at your gas consumption and see if the extra expence & labor for high efficiency is worth it. It's just a math calculation.

Other than that, I have been told that their are only a few companies that make water heaters. Most brands are just rebadged. I don't have an opinion on which is better

Danny Scully

Have you considered ditching them both and installing an everhot external heat exchanger? You'll likely have plenty of heat transfer with that big beautiful steamer. I'll even make a bold prediction that you won't ever run or of hot water.

kcopp

Is your current chimney lined? You prob will need to line it if you install a natural vent water heater.
Don't get too wrapped up in 1st hour ratings. You need storage.
24 years is VERY good for a gas water heater.
I would get a pro to install it and add a secondary anode rod to the tank to boost the life of it.
Having a pro to install will allow there to be someone in your corner to work out any warranty issue should they arrive.

cubicacres

I'm not familiar with heat exchangers-would that work with our single-pipe steam boiler or have efficiencies for combining them if we keep usually keep the boiler off in summer? We were thinking running the boiler to heat water might not be as efficient, but not sure how that would work out over the warm summers & cold winters here in Milwaukee, WI.

I think we have a basic chimney liner (maybe clay?) when we looked into our boiler replacement, but were considering upgrading until our boiler installers told us it wasn't necessary at the time. Both water heaters & our steam boiler vent to the chimney currently.

Can a 2nd anode rod be used/added if the top has an additional tapping, or would we need to select a model that already has 2 rods installed from the manufactuer?

ratio

Drilling the brick might not be as expensive as you think. I bought a 4" diamond bit and a cheapo wet core drill, brand new, on eBay for under $300. And I'm fairly sure I could have had it drilled professionally for around that as well. But now I have a core drill if my own!

kcopp

An additional anode can be bought from the manufacturer. State sells the extra anode that fits into the hot tapping and acts as a dielectric nipple

Steamhead

I'd stay away from A.O. Smith- some of their units have been troublesome, and their customer service is iffy. Rheem and Bradford-White should do OK.

newagedawn

a o smith, rheem , rudd, brandford and white are all good

hot_rod

Lochinvar, & Bradford White are a couple top brands, although not commonly seen at box stores.

Bock is a Wisconsin brand, I don't know what type of residential offering they have. The have a unique gas/ solar fired tank.

HTP has a good rep/ dealer in your area. The stainless Phoenix would be one to look at for 90% plus efficiencies.

cubicacres

Thanks for the suggestions. It sounds like you've involved with more than just steam boilers

HVACNUT

If you have the height, how about 1 commercial water heater?

cubicacres

We were considering combining the 2013 40 gallon & 1993 50 gallon into one, but were reluctant to get rid of the 2013 installed one since it's newer. Is there much savings on 2 40 gallon heaters vs one 80 gallon to justify it over time?

The commercial ones we saw were $3,000+, compared to the residential ones around $400-600. For 9 people in the building with 5 bathrooms & kitchens with no dishwashers & 1 washing machine, would you reccomend residential vs. commercial water heaters given the price & demand of the building?

hot_rod

Do the current units keep up with the loads and are the tenants happy with the DHW provided? If so, the least expensive would be to replace the older unit with a like sized residential unit.

If you need more DHW, or want to lower operating costs, going to one commercial high efficiency unit might be your route.

Just pencil out the upfront installed cost vs the projected savings over 10- 15 years.

Often on rental units it is as much about providing sufficient DHW to the renters.

cubicacres

Thanks, we have sufficient hot water supply for everyone. Last year someone mentioned it was cooler in the shower, so we turned it up from the arrow setting to the between the arrow & the A temp. setting, and all has been fine since then.

Can the BTUs used be compared to get an estimate of energy cost? If we have 2 40K BTUs water heaters, for example, is that similar to one larger 80K BTU unit in operating costs? Having the 2nd unit for when one fails seems nice, so I guess there are some trade-offs with 2 vs one.

We thought we were ok when we tightened the plastic drain valve and it stopped the leak for a day or two, but it's leaking again. So now we're deciding if we should just repalce the drain valve on the 1993 heater or repalce it. I don't think maintenance was done on it, so from a new Vangurd 50 gallon .58 Energy rating in 1993 & to what it's operating at now vs. a new .62 rated one, we're wondering if it will pay for itself if we replace it and follow the blow-down & anode rod changes as reccomended in the manual on a new one. Any ideas on how to estimate current efficient on an older unit?

j a_2

Does your local code allow for a commercial appliance to be used in a residential building.?

hot_rod

One large tank would, in theory have less heat loss through the jacket as it is all about the amount of surface area. Tank style water heaters are fairly reliable, I doubt you would be down for very long if a control failed, for example.

Be careful when you crank up the tank temperature, 120- 122F is about all you want to supply to the faucets for safety and possibly code compliance. If you do increase tank temperature to provide more DHW capacity, and or anti legionella function, add a listed thermostatic mixing valve at the tank(s)

Zman

If you go the conventional gas route, I would suggest one with a power damper on the flue and electronic ignition. It is amazing how much waste there is in standby loss up the flue and a standing pilot.

L Thiesen

I have a 50 gal nat gas water heater at my house, in summer my gas usage is app $8.00 per month and that's with my gas grill on the same line. I doubt a vent damper and spark ignition would give me any payback and would not be as trouble free.

cubicacres

Sounds like there are some similarities between steam boilers & hot water heaters regarding spark ignition, vent dampers, etc.

With the commercial heaters being a few thousand $ more than the residential units we saw, we're thinking just swapping for another residential 40 gallon tank would be best for us. Both Lowe's AO Smith & Home Depot Rheem (maybe also made by AO Smith) have plastic drain valves Has anyone replaced the drain valves when installing it with brass, or is better to wait until the plastic fails? That being said, with our 1993 unit's valve failing, what usually causes people to give up and buy an new unit in the end?

With both heaters connected, if one goes out does it usually mean the remaining one will supply the building fine until the hot water is exhausted earlier with the lower total capacity? One suggestion was to leave the 2013 40 gallon 55 1st Hr. Hotpoint 34K BTU heater alone, and see if that's enough for the 9 residents/5 bathrooms with no dishwashers & 1 washing machine in the basement. We didn't think that would be enough capacity unless everyone times their showers 30 minutes apart though.

hot_rod

Most all of the water heater manufacturers sites have sizing information. Choose the building type, number of occupants and get the suggested size tank.

So either you guesstimate, track actual usage for a few months with a watermeter, or use the industry sizing guidelines to size the tanks.

It's been my experience that tenants will use all the DHW available, or learn to limit their use if the system is undersized. Or call and complain

This is a handy simulator at the Lochinvar site that shows the extra capacity available by raising the tank temperature and installing a mixing valve.

From a liability standpoint, in a rental property like that I would include a thermostatic mixing valve.

Zman

L Thiesen said:

I have a 50 gal nat gas water heater at my house, in summer my gas usage is app $8.00 per month and that's with my gas grill on the same line. I doubt a vent damper and spark ignition would give me any payback and would not be as trouble free.

Given your unusually light usage, I would recommend sticking with the most wasteful appliance you can find.

ratio

Zman said:

Given your unusually light usage, I would recommend sticking with the most wasteful appliance you can find.

What's the payoff time to replace a working water heater with a new high efficiency model with that kind of usage?

Zman

The original question was about replacing a failing water heater and making good long term decision. There are a lot of good suggestions on how to go about this in this post.

I would contend that if you have normal DHW usage and want to go with a less expensive conventional gas heater, it is worth the extra money to buy one with electronic ignition and power damper.

I would love to see a copy of the $8 gas bill. The standing pilot all by itself uses almost that much...

ratio

Sorry if I came across as a little short.

BobC

Regular tank type gas hot water heaters can be a good choice if you have reasonable hot water needs. In the summer my gas usage is 5-6 therms, that includes the has water heater and the stove. I usually only use the stove for making coffee in the morning, supper is from the bbq.

i have records going back a decade and the summer usage is always about the same, a shower in the morning and wash a few dishes at night. When I had the steam boiler replaced he asked if I wanted an indirect, I told him I'm fine thanks.

Bob

cubicacres

We use about 30 therms of gas per month in the summer with both standard atmospheric water heaters (40 & 50 gallon in the boiler room for 9 people with 5 bathrooms).

Any thoughts on US Craftmaster vs. Richmond heaters? I think the 5-6 brands we saw are all made by 2 companies so far (AO Smith & Rheem, I think?). They told me the virtually identical units have different tags on them & different length warranties for the most part.

Larry Weingarten

Hello, Some companies are now giving pro-rated warranties on water heaters... like tires. Skip this and make sure you get a full warranty. Personally, I go for a six year warranty, but then add a second magnesium anode for long life.

Yours, Larry

cubicacres

Thanks, we'll figure it out and probably replace the leaking one next week.