Water Heater type and sizing help needed
I remodelled a home into a duplex and live in half, rent half. The electric water heater (shared by both units) is going out and I’ve noticed in the past when we and the renters all try to wash clothes (two utility rooms), and fill bathtubs we can run out of hot water. Since I’m replacing the tank, I want to do it right.
I can get a 80 gal 12-yr electric that would be easy to install myself for about $450. I would hope it would do the job with a first-hour rating of 93 gallons. However, we have gas available within 10 feet that is feeding our boiler for our hot water baseboard system. I’m wondering if perhaps I should be looking at a gas water heater? The largest one I can get that will fit in the available space is 50 gallons with a first-hour rating of 89 gal, not too shabby compared to the electric. I don’t have a hard cost on the gas heater, but I’d defer to an installer to hook up the gas and flue, so it’ll probably cost me in the $700.00 range to get it instlalled.
A few questions:
1. I have a brochure with all the heaters on it and it indicates estimated cost of operation of the electric at $400/yr, compared to $167/yr for the gas. REALLY that much different? They don’t have any “based on .10/kwh” kind of legend on the comparison sheet. Does gas really save that much, generally?
2. Will the gas heater keep up with the heavy demand we sometimes create? Will the electric?
3. If you were in my shoes, what would you be looking at doing?
TIA for your help.
PS: this comparison brochure drives me nuts. They have recovery rates for gas heaters, but not electric!
Replies
From your post I am assuming that you have natural gas, and if that is the case then the numbers are pretty close for the cost savings. the general rule of thumb is natural gas, oil, propane, than electric in order of choice. If I was to do it I would use the gas or check into using the boiler with a heat exchanger with a large storage tank. Boilers just make a bunch of hot water and do it very fast. Good Luck.
The savings over the life of the unit will vary depending on local costs, but in many (most?) cases the return on investment (read "savings") on the additional cost of a gas dryer would make the stock market's performance in the '90s look anemic.
I'd be surpised if the installation cost is as much as you're thinking, but you need to get a hard quote for your area and situation.
Can the boiler be retrofitted for domestic HW?
Mike
It's O.k. to think out of the box, Just don't walk off of the plank!
Probabaly. It has 2 "zones" on it for the different dwelling units, and if I had a transfer tank installed, it could simply have a third zone. The piping (in and out) and the zone therostats .etc. for the boiler is within 3 feet of the existing water heater. I've actually considered that as an option, but have no experience with those units, so probably gave it less weight as a possiblilty.
The best option is an indirect fired water heater working off of your boiler with priority relay wiring. For a small fee I can guide you through it over the phone and with wiring and piping schematics customized for your application.
Are you in PA? If so I'll even sell you a top of the line, brand new, out of the box unit for $600 (slightly negotiatable). You would have to pick it up. This is a unit that I usually pay $749 (WHOLESALE ). Why would I sell it for 150 bucks less? This unit is in PA and I live in CO!!!
I will be getting it picked up on Tuesday and hauled to WV where at the end of July I will have it brought on out to CO, so if you want it let me know OK?
I'm getting very interested in this option; I'm in Seattle area... not quite PA or WV or CO....
If anyone knows a good reputable dealer of these things in the Seattle area, I'd like to know... I contacted a Water Heater replacement co today (we have 3 or 4 in the Seattle phone book) who said they'd come out and give me all my options, and be prepared to install TODAY, they carry 10 units in their truck; if I didn't buy today, it would be an $80.00 estimate fee... GRR! I'm not quite ready to buy. If I were in a bind and an avg. joe homeowner, I could see going with them if my WH was toast, but that kind of sales practice makes me fume....
What isn't discussed is energy loss with Gas verses Electric.
Gas is vented outside. That means there is a four inch hole in the roof. 24/7 for the life of the unit. Heat will go out that hole either in the form of exhaust gas or just plain room heat. Just imagine what your heat bill is if you crack a window open say one inch and leave it that way all winter... Since most heaters are installed in the basement or ground floor and heat rises, aditional heat will be lost since the opening is in the roof. In addition the flue is metal, it will conduct the cold down into the house.
I've never seen this analized completely and wish I could see the real figures. especially when you cansider the super insulated/sealed homes of today.
That's a good point; in my case, my boiler for the hydronic system is already outside, so if I were to piggy back off it to get hot water, there would be no additional boiler or flue needed.... It's sounding better all the time.
Frenchy I would not put the vent pipe straight up to the roof, but vent out to the side.
"Frenchy I would not put the vent pipe straight up to the roof, but vent out to the side"
Please be aware that there are some you can vent out the side, but they cost much more.
I've just started to see the High effiecency water heaters that vent sideways, So far none of the ones I've seen provide make-up air in a sealed unit. Since they don't, the air they consume must come from someplace and since nature abhors a vacum, they will suck cold air in to replace the air that is burned and sent out the exhaust. Thus there is a double whammy loss of heat out the exhaust and the vacum sucking outside cold air in.
Indirect fired storage tank off the boiler
I installed an indirect water heater that runs off a circulator from the boiler. It wasn't too hard to do. It is a 65 gal and provides around 145 gal. for the first hour. I also put low-flo shower heads, and there are two in each stall. This is the set up for a duplex, and with eight people, we have never run out of hot water. This system has the great advantage of "free Hot Water" when the boiler is all ready running in the winter. The new 40 gal Thermo-Flo water heater I am planning to install in my new house is stainless steel, guaranteed for life and has the same capacity for hot water as the old designed 65. They also sell direct fired heaters too. I recommend the indirect system if you can get it hooked up. I think the initial cost(750) would quickly pay for itself in energy savings and warm showers.
What brand and model of the indirect-fired wh did you get for the 65 gal? I've been looking at Amtrol, and the local plumbing supply store that carries them priced the 60 gal single-wall around $1000. Then I need a zone valve and some fittings and I'm nearly there. I'd love to get in for closer to $750 if I could. (The local installer quoted me $2500 parts and labor and suggested if I could buy from the supply house I do it myself or hire a plumber for a couiple hours).
Anyway, if you could share some details with me, I'd be grateful. I haven't bought anything yet, but am on the verge of getting something very soon.
The 65 gallon is also a thermo-flo. They discontinued this brick lined model for the afore-mentioned stainless steel model with a spiral heat exchanger, instead of the older replaceable U-shaped one. This has made the new one even more efficient. To install the indirect WH to my hydronic system, I just did as they had done, adding a zone, with the needed valves, drain ####, a Taco 007 circulator pump, electrical controller and then either plumbed or wired as the other zones were, if all else failed, followed the directions. I had never done this before, and believe that if you can sweat a pipe and follow a wiring diagram you could do it too.
As others have said, natural gas tends to be the cheapest to operate, but it depends on your local electric and gas rates.
I personally like a gas unit, and particularly like the new power vent models with the PVC chimney. They're more efficient, and don't require a roof penetration. (Which could be a problem for you - Going from electric to gas)
Someone brought up the issue with makeup air. You need makeup air for ANY gas water heater. Why would the power vented models be any different? At least they can't backdraft CO2 into the living area.
Always try to be modest, and be proud of it.
Someone brought up the issue with makeup air. You need makeup air for ANY gas water heater. Why would the power vented models be any different? At least they can't backdraft CO2 into the living area.
The power venterd ones move a lot more air. We can side vent 'em (below windows, for example) because the combustion gases have been extremely diluted so even huge amounts of CO in the combustion gases won't (at least in theory) cause CO risks. (Per the instructort at my Bacharach CO testing course.)
As a home inspector and BPI certified Carbon Monoxide Analyst, I recommend a good quality CO detector (the type with an LED readout) in any room with a window above the vent or a low level CO monitor (see, e.g., http://www.aeromedix.com) if anyone in the hosue is at higher risk: pregnant, infants, elderly, people with heart problems, people with chemical sensitivities, etc.
FWIW, Some older models didn't have any inter-connect between the draft blower and the burner, blower goes out, flue gases all end up in the house.
Also, CO in the house is possible if the vent comes loose.
I also wonder if those things would continue to operate if the inner baffle should come loose and block the internal flue in the water heater and back up combustion gases (including likely high amounts of CO) through the combustion chamber itself.
That's a theoretical concern, I don't know if the modern safety interconnects would work in a case like that.
Bob,
How are you, haven't seen you posting much in a while?
" I recommend a good quality CO detector (the type with an LED readout) in any room with a window above the vent.."
A pet peeve I have with building codes as applied to residences, is that in the place where there is the greatest potential to harm people, the codes are the least restrictive. In a house, you stick a vent directly under windows, and most codes do not restrict the distance to a window or door. In non-residential applications, 10 minimum must be maintained. A good idea to apply this to houses. Some building types require 15 feet.
"I also wonder if those things would continue to operate if the inner baffle should come loose and block the internal flue in the water heater and back up combustion gases (including likely high amounts of CO) through the combustion chamber itself."
Most induced draft (i.e. power vented) DWH have a very simple safety logic. They would continue to operate if the fan pressure switch "saw vent flow" and the hood high temp wasn't tripped.
As an employee at a water heater company, I am not surprised that you are shocked at the cost to heat water using electricity vs. gas. The numbers you quote are true...perhaps too low for the electricity..I usually quote $450/yr.
You don't find recovery rates for electrics because they are soo poor. A gas will recovery very, very fast compared to an electric.
I would definitely convert to gas, the money you invest will be made back in a year or two in energy savings. I would ask a distributor about sizes. I would guess the 50 gal. gas would be OK but there may be models with a slightly higher capacity which would fit in your space.
One piece of advice, look for the gas model with the highest Energy Factor, EF, rating. The higher rated units are more expensive but will be well worth it over a 12 or 15 year heater lifetime.
Bill