FHB Logo Facebook LinkedIn Email Pinterest Twitter X Instagram Tiktok YouTube Plus Icon Close Icon Navigation Search Icon Navigation Search Icon Arrow Down Icon Video Guide Icon Article Guide Icon Modal Close Icon Guide Search Icon Skip to content
Subscribe
Log In
  • How-To
  • Design
  • Tools & Materials
  • Restoration
  • Videos
  • Blogs
  • Forum
  • Magazine
  • Members
  • FHB House
  • Podcast
Log In

Discussion Forum

Discussion Forum

Water Heater type and sizing help needed

geoffhazel | Posted in Energy, Heating & Insulation on June 28, 2002 09:23am

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! 

Reply
  • X
  • facebook
  • linkedin
  • pinterest
  • email
  • add to favorites Log in or Sign up to save your favorite articles

Replies

  1. blackcloud | Jun 28, 2002 12:56pm | #1

    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.

  2. User avater
    rjw | Jun 28, 2002 01:28pm | #2

    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.

  3. User avater
    MikeS | Jun 28, 2002 07:31pm | #3

    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!
    1. geoffhazel | Jun 28, 2002 09:17pm | #4

      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.

      1. Wet_Head | Jun 29, 2002 06:21am | #6

        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?

        1. geoffhazel | Jun 29, 2002 07:42am | #7

          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....

          1. fdampier | Jun 29, 2002 05:01pm | #8

            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.

          2. geoffhazel | Jun 29, 2002 06:55pm | #9

            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.

          3. 55512122 | Jun 30, 2002 04:45pm | #10

            Frenchy I would not put the vent pipe straight up to the roof, but vent out to the side.

          4. User avater
            rjw | Jun 30, 2002 10:34pm | #11

            "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.

          5. fdampier | Jul 03, 2002 05:35am | #12

            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.

  4. KCPLG | Jun 29, 2002 05:45am | #5

    Indirect fired storage tank off the boiler

  5. GregAlbright | Jul 03, 2002 07:57am | #13

    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.

    1. geoffhazel | Jul 03, 2002 08:04am | #14

      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.

      1. GregAlbright | Jul 05, 2002 07:39am | #17

        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.

  6. User avater
    BossHog | Jul 03, 2002 03:09pm | #15

    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.

    1. User avater
      rjw | Jul 05, 2002 01:59pm | #18

      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.

      1. TLRice | Jul 12, 2002 02:41pm | #19

        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.

  7. BillHoover | Jul 05, 2002 12:32am | #16

    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

Log in or create an account to post a comment.

Sign up Log in

Become a member and get full access to FineHomebuilding.com

Video Shorts

Categories

  • Business
  • Code Questions
  • Construction Techniques
  • Energy, Heating & Insulation
  • General Discussion
  • Help/Work Wanted
  • Photo Gallery
  • Reader Classified
  • Tools for Home Building

Discussion Forum

Recent Posts and Replies

  • |
  • |
  • |
  • |
  • |
  • |
View More Create Post

Up Next

Video Shorts

Featured Story

Making the Move to Multifamily

A high-performance single-family home builder shares tips from his early experience with two apartment buildings.

Featured Video

Micro-Adjust Deck-Baluster Spacing for an Eye-Deceiving Layout

No math, no measuring—just a simple jig made from an elastic band is all you need to lay out a good-looking deck railing.

Related Stories

  • Guest Suite With a Garden House
  • Podcast Episode 688: Obstructed Ridge Vent, Buying Fixer-Uppers, and Flashing Ledgers
  • FHB Podcast Segment: Finding the Right Fixer-Upper
  • Keeping It Cottage-Sized

Highlights

Fine Homebuilding All Access
Fine Homebuilding Podcast
Tool Tech
Plus, get an extra 20% off with code GIFT20

"I have learned so much thanks to the searchable articles on the FHB website. I can confidently say that I expect to be a life-long subscriber." - M.K.

Get home building tips, offers, and expert advice in your inbox

Signing you up...

This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
See all newsletters
See all newsletters

Fine Homebuilding Magazine

  • Issue 332 - July 2025
    • Custom Built-ins With Job-Site Tools
    • Fight House Fires Through Design
    • Making the Move to Multifamily
  • Issue 331 - June 2025
    • A More Resilient Roof
    • Tool Test: You Need a Drywall Sander
    • Ducted vs. Ductless Heat Pumps
  • Issue 330 - April/May 2025
    • Deck Details for Durability
    • FAQs on HPWHs
    • 10 Tips for a Long-Lasting Paint Job
  • Issue 329 - Feb/Mar 2025
    • Smart Foundation for a Small Addition
    • A Kominka Comes West
    • Making Small Kitchens Work
  • Issue 328 - Dec/Jan 2024
    • How a Pro Replaces Columns
    • Passive House 3.0
    • Tool Test: Compact Line Lasers

Fine Home Building

Newsletter Sign-up

  • Fine Homebuilding

    Home building tips, offers, and expert advice in your inbox.

  • Green Building Advisor

    Building science and energy efficiency advice, plus special offers, in your inbox.

  • Old House Journal

    Repair, renovation, and restoration tips, plus special offers, in your inbox.

Signing you up...

This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
See all newsletters

Follow

  • Fine Homebuilding

    Dig into cutting-edge approaches and decades of proven solutions with total access to our experts and tradespeople.

    Start Free Trial Now
    • Facebook
    • Instagram
    • X
    • LinkedIn
  • GBA Prime

    Get instant access to the latest developments in green building, research, and reports from the field.

    Start Free Trial Now
    • Facebook
    • YouTube
  • Old House Journal

    Learn how to restore, repair, update, and decorate your home.

    Subscribe Now
    • Facebook
    • Instagram
    • X
  • Fine Homebuilding

    Dig into cutting-edge approaches and decades of proven solutions with total access to our experts and tradespeople.

    Start Free Trial Now
    • Facebook
    • Instagram
    • X
    • LinkedIn
  • GBA Prime

    Get instant access to the latest developments in green building, research, and reports from the field.

    Start Free Trial Now
    • Facebook
    • YouTube
  • Old House Journal

    Learn how to restore, repair, update, and decorate your home.

    Subscribe Now
    • Facebook
    • Instagram
    • X

Membership & Magazine

  • Online Archive
  • Start Free Trial
  • Magazine Subscription
  • Magazine Renewal
  • Gift a Subscription
  • Customer Support
  • Privacy Preferences
  • About
  • Contact
  • Advertise
  • Careers
  • Terms of Use
  • Site Map
  • Do not sell or share my information
  • Privacy Policy
  • Accessibility
  • California Privacy Rights

© 2025 Active Interest Media. All rights reserved.

Fine Homebuilding receives a commission for items purchased through links on this site, including Amazon Associates and other affiliate advertising programs.

  • Home Group
  • Antique Trader
  • Arts & Crafts Homes
  • Bank Note Reporter
  • Cabin Life
  • Cuisine at Home
  • Fine Gardening
  • Fine Woodworking
  • Green Building Advisor
  • Garden Gate
  • Horticulture
  • Keep Craft Alive
  • Log Home Living
  • Military Trader/Vehicles
  • Numismatic News
  • Numismaster
  • Old Cars Weekly
  • Old House Journal
  • Period Homes
  • Popular Woodworking
  • Script
  • ShopNotes
  • Sports Collectors Digest
  • Threads
  • Timber Home Living
  • Traditional Building
  • Woodsmith
  • World Coin News
  • Writer's Digest
Active Interest Media logo
X
X
This is a dialog window which overlays the main content of the page. The modal window is a 'site map' of the most critical areas of the site. Pressing the Escape (ESC) button will close the modal and bring you back to where you were on the page.

Main Menu

  • How-To
  • Design
  • Tools & Materials
  • Video
  • Blogs
  • Forum
  • Project Guides
  • Reader Projects
  • Magazine
  • Members
  • FHB House

Podcasts

  • FHB Podcast
  • ProTalk

Webinars

  • Upcoming and On-Demand

Podcasts

  • FHB Podcast
  • ProTalk

Webinars

  • Upcoming and On-Demand

Popular Topics

  • Kitchens
  • Business
  • Bedrooms
  • Roofs
  • Architecture and Design
  • Green Building
  • Decks
  • Framing
  • Safety
  • Remodeling
  • Bathrooms
  • Windows
  • Tilework
  • Ceilings
  • HVAC

Magazine

  • Current Issue
  • Past Issues
  • Magazine Index
  • Subscribe
  • Online Archive
  • Author Guidelines

All Access

  • Member Home
  • Start Free Trial
  • Gift Membership

Online Learning

  • Courses
  • Project Guides
  • Reader Projects
  • Podcast

More

  • FHB Ambassadors
  • FHB House
  • Customer Support

Account

  • Log In
  • Join

Newsletter

Get home building tips, offers, and expert advice in your inbox

Signing you up...

This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
See all newsletters
See all newsletters

Follow

  • X
  • YouTube
  • instagram
  • facebook
  • pinterest
  • Tiktok

Join All Access

Become a member and get instant access to thousands of videos, how-tos, tool reviews, and design features.

Start Your Free Trial

Subscribe

FHB Magazine

Start your subscription today and save up to 70%

Subscribe

Enjoy unlimited access to Fine Homebuilding. Join Now

Already a member? Log in

We hope you’ve enjoyed your free articles. To keep reading, become a member today.

Get complete site access to expert advice, how-to videos, Code Check, and more, plus the print magazine.

Start your FREE trial

Already a member? Log in

Privacy Policy Update

We use cookies, pixels, script and other tracking technologies to analyze and improve our service, to improve and personalize content, and for advertising to you. We also share information about your use of our site with third-party social media, advertising and analytics partners. You can view our Privacy Policy here and our Terms of Use here.

Cookies

Analytics

These cookies help us track site metrics to improve our sites and provide a better user experience.

Advertising/Social Media

These cookies are used to serve advertisements aligned with your interests.

Essential

These cookies are required to provide basic functions like page navigation and access to secure areas of the website.

Delete My Data

Delete all cookies and associated data