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  1. #1

    Question california homeowner needs advice

    Yes, I'm a homeowner, but I'm also a licensed electrician so I understand that you don't want to give away advice and info that someone else in your trade may charge for.

    I have a house in the San Francisco Bay Area that my Dad built in around 1978. It's somewhere around 2000 sq ft, and has two levels separated by a wide open staircase. Living room, family room, and kitchen on main floor, three bedrooms and two bathrooms on the second floor. the entire main floor has exposed beam high ceilings with an almost entire wall of windows. There are also skylights, and some windows that are single pane.

    I'm trying to invest in my future and make the house more energy efficient and also be more comfortable keeping the temperature comfortable without feeling like my heat is all escaping. So, I've been installing dual pane windows when I can afford it, putting plexiglass on the ceiling over the skylights to artificially dual-pane them. Overall the house is well-built and well-insulated, but at the same time it does seem to lose heat quickly so I'm just not comfortable keeping the temperature comfortable, also because I rented out a couple of bedrooms and we split the bill, so they'll ***** about the utility bill if it gets too high. I'm sure it wouldn't be TOO much if I just set the thermostat at 68 and let it just do whatever it has to do, but I really feel like it will be cycling a lot. The other problem is that the thermostat is on the main floor, so I would also kind of imagine that the upstairs will get too hot before the leaky downstairs (high ceilings, single pane sliding glass door, single pane kitchen windows, etc.) gets warm enough for the thermostat to shut it down.

    The ducts are all hard-pipe and wrapped with bare fiberglass insulation.

    My Dad said that the furnace was over-sized (not good?). It's a 140,000 BTU Rheem RGAA-14BA that was installed at the time the house was built.

    So, here are my questions. Before I ask, I would like to thank everyone for reading this and hopefully giving me advice! And, I know I have a lot of nerve joining this forum just to ask this question and in reality probably not able to give anything back to these fine folks. (I'll support the sponsors/advertisers though)

    1. Does anyone have an idea of the approximate AFUE rating of this furnace? I know you won't be able to give me an exact #, but is there a rule of thumb like "over 100k BTU before 1980, probably around 75%" or something?

    2. Does it seem oversized based on any general rule of thumbs?

    3. This is a subjective question that depends on financial situation and so on, but do you think it makes sense to replace the furnace with a more efficient one?

    4. What do you all think of these 2-stage furnaces? I've read a little about them and they seem neat, but you all are the experts.

    Anyway, you can see where I'm going with this. I want to invest in my energy-efficient future and replacing the furnace at some point is going to be part of this...along with many other things...dual pane windows and skylights, weatherstripping for doors, compact fluorescents, etc.

    THANK YOU ALL and MERRY CHRISTMAS!

  2. #2
    Join Date
    Mar 2005
    Location
    Suppy NC
    Posts
    4,513
    78-08
    that furnace is a few days from 30 years old and eff is just not there any more. It has also lived 10 years past the normal life for a furnace and has given someone thier monies worth

    time for a new one

    size can only be decided by a heat loss calc. Any other way is guessing and waisting money

    get some prices and have a load done so you can make a more knolegeable decision

  3. #3
    Join Date
    Jun 2007
    Location
    louisville ky
    Posts
    107
    im not a pro but i had a duel fuel put in last summer.seer14 heatpump and a 95% furnace. i love the heatpump the air is not dry and it is alot cheaper to run. you may want to look in to a duel fuel. i will never have anything other than duel fuel

  4. #4
    Join Date
    Dec 2006
    Location
    Middle Tennessee
    Posts
    11,347

    *

    Quote Originally Posted by chrism9232 View Post
    im not a pro but i had a duel fuel put in last summer.seer14 heatpump and a 95% furnace. i love the heatpump the air is not dry and it is alot cheaper to run. you may want to look in to a duel fuel. i will never have anything duel fuel
    is that a typo?



    .

  5. #5
    Join Date
    Jun 2007
    Location
    louisville ky
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    107
    Quote Originally Posted by Airmechanical View Post
    is that a typo?



    .
    thanks

  6. #6
    Join Date
    Jul 2004
    Location
    Massachusetts
    Posts
    6,837
    Quote Originally Posted by needfurnacehelp View Post
    So, I've been installing dual pane windows when I can afford it, putting plexiglass on the ceiling over the skylights to artificially dual-pane them.
    Installing new windows without first having a blower door test done on the home is possibly wasting your hard earned money. Please read on.

    Overall the house is well-built and well-insulated, but at the same time it does seem to lose heat quickly...
    You're probably right, that the home is losing heat quickly. However, insulation is NOT the answer if your house is bleeding/leaking treated air to the outdoors. To prove the point, try opening a window on a windy day and hold some insulation up to block the opening. You'll find the wind comes right through. That's the same result you'll get putting insulation in trying to block any air trying to escape your home. It is imperative that you find the air leaks and seal them, then insulate to minimize conduction heat losses. Once you plug all the other leaks, you may find that the little leaks around some of your windows are just right to allow for proper air exchange in the home. After all, if you wanted fresh air on a nice day, what would you do? Go sniff in the walls, the attic, the basement or open a window? Same thing. Seal the leaks to/from the walls, ceiling to attic, basement to treated spaces first, then insulate to stop conduction heat loss. Do the windows last if necessary and then do only as many as you need to do to keep the required air exchanges in the home (determined by a blower door test).

    The ducts are all hard-pipe and wrapped with bare fiberglass insulation.
    Hard pipe is good, as long as it's thoroughly sealed. Unsealed ducts can have air losses of as high as 30% according to reports done by the DOE.

    [Quote]My Dad said that the furnace was over-sized (not good?). It's a 140,000 BTU Rheem RGAA-14BA that was installed at the time the house was built./Quote]

    You should have a thorough, room-by-room hand load analysis done (Manual 'J') so there will be no conjecture on what size the furnace should be.

    1. Does anyone have an idea of the approximate AFUE rating of this furnace? I know you won't be able to give me an exact #, but is there a rule of thumb like "over 100k BTU before 1980, probably around 75%" or something?
    If your furnace has a standing pilot, the best you can hope for is 65% but likely lower.

    2. Does it seem oversized based on any general rule of thumbs?
    Again, a Manual 'J' heat load analysis is the only real way to tell and ideally, that would be referenced to the results of a blower door test that will tell you how much your home actually leaks. Duct losses can also be measured during a blower door test if the testing company has an airflow hood.

    3. This is a subjective question that depends on financial situation and so on, but do you think it makes sense to replace the furnace with a more efficient one?
    I'd replace the furnace only after A. Having a blower door test done and sealing as much of the problem areas as possible, as this will change the needed output of the replacement furnace and B. After a proper load analysis to determine the proper equipment size.

    4. What do you all think of these 2-stage furnaces? I've read a little about them and they seem neat, but you all are the experts.
    I think extremely highly of all 2-stage or modulating equipment, including furnaces, boilers, air conditioners and heat pumps. Personally I'm installing a 2-stage high efficinecy heat pump as primary heat until the outdoor temperature drops to 38-degrees, when my oil hot water system will take over. This is called a Hybrid Heat system (Bryant) or dual fuel system, which gives you the option of running either the fossil fuel system or the heat pump and you can select whether you want the changeover to occur for comfort or economy reasons. Obviously the cost of operation of the heat pump (electricity) or gas furnace (fossil fuel) is different in each area so you'd have to do some math to determine what's most satisfactory for you. Also, a duel fuel system shift the greenhouse gas issue from you to the electric utility when you're not using the gas furnace. That makes you 'greener' and the likelihood that the government will regulate the electric company emissions is far more likely than regulating homeowners greenhouse emissions. So that's a step in the 'green' direction.
    Last edited by skippedover; 12-09-2007 at 08:23 PM.
    If YOU want change, YOU have to first change.

    If you are waiting for the 'other guy' to change first, just remember, you're the 'other guy's' other guy. To continue to expect real change when you keep acting the same way as always, is folly. Won't happen. Real change will only happen when a majority of the people change the way they vote!

  7. #7
    Join Date
    Dec 2004
    Posts
    441

    sparkey

    Could you help me find a website that electricians visit on a frequent basis? I prefer a website that I can ask questions about how I can do your job without actually hiring you, you know, I can do your job without your experience, that is, what is your trade?

  8. #8
    Join Date
    Apr 2001
    Location
    san jose,ca.
    Posts
    5,285
    What city in the bay area are you in?

  9. #9
    Join Date
    Nov 2007
    Location
    Livermore, Ca
    Posts
    163
    [QUOTE=needfurnacehelp;1695804]Yes, I'm a homeowner, but I'm also a licensed electrician so I understand that you don't want to give away advice and info that someone else in your trade may charge for.

    Spread the love, Bro

  10. #10
    Join Date
    Oct 2004
    Location
    OZ Aka SW Florida
    Posts
    1,830
    Quote Originally Posted by bigbird View Post
    What city in the bay area are you in?
    Chicken Land...CLUCK>>>
    Refrigeration...Finding the Wright Wrench to pound in the correct..Screw

  11. #11
    Quote Originally Posted by bigbird View Post
    What city in the bay area are you in?
    I'm in San Carlos, how about you?

  12. #12
    Join Date
    Nov 2004
    Location
    SW FL
    Posts
    6,287
    Quote Originally Posted by needfurnacehelp View Post

    I have a house in the San Francisco Bay Area that my Dad built in around 1978. It's somewhere around 2000 sq ft,

    My Dad said that the furnace was over-sized (not good?). It's a 140,000 BTU Rheem RGAA-14BA that was installed at the time the house was built.

    1. Does anyone have an idea of the approximate AFUE rating of this furnace? I know you won't be able to give me an exact #, but is there a rule of thumb like "over 100k BTU before 1980, probably around 75%" or something?

    2. Does it seem oversized based on any general rule of thumbs?

    3. This is a subjective question that depends on financial situation and so on, but do you think it makes sense to replace the furnace with a more efficient one?
    http://www.hvacopcost.com/

    1. 77% originally ( now 65% might be generous.)

    2. 80,000 would be my "2-mimute thought" on estimated MAX.

    3. You might be able to save > $400/year with a higher efficiency furnace.
    Pay-back period is for you to determine.

    DuAl fuel set-up should be investigated. ... and I am NOT a fan of RHEEM.

    CA electric /gas rates likely make it a border line case for using heat pumps at < ~ 40'F based on energy savings.
    However, if you wish to have A/C, then new heat pump should be selected.
    Designer Dan
    It's Not Rocket Science, But It is SCIENCE with "Some Art". ___ ___ K EEP I T S IMPLE & S INCERE

    Define the Building Envelope and Perform a Detailed Load Calc: It's ALL About Windows and Make-up Air Requirements. Know Your Equipment Capabilities

  13. #13
    Join Date
    Nov 2007
    Location
    Livermore, Ca
    Posts
    163
    Quote Originally Posted by dan sw fl View Post
    DuAl fuel set-up should be investigated. ... and I am NOT a fan of RHEEM.
    What are the brands that you do prefer?

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