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  1. #1
    Join Date
    Jun 2008
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    5

    An epic question

    You guys probably get questions like this all the time, but I couldn’t find the answers I was looking for going back through the forum, so I thought I’d just ask myself.

    Background:
    My wife and I bought a townhouse in a Minneapolis suburb less than a year ago. We’ve had a lot of fixes in that year, but we now have a problem with the AC. It appears to be leaking refrigerant, and the charge to find and repair the leak was higher than I expected. The house was built in 1995, but a tag on the furnace panel notes that at least the furnace was actually constructed in 1990. Given the age of the system we believe replacing the AC is probably the best choice.

    We’ve had 5 estimates so far and they are all fairly close, but I had a few questions. If anyone can be of any help on any or all of these questions, that would be helpful

    1.The furnace still works fine. It does have some rust in the system; don’t know how long it’s been rusty. Wish our home inspector had caught that at closing. The big question for us is this: Should we replace the furnace at the same time we replace the AC? Obviously, the contractor will give us a sizable discount to buy together, but if the furnace lasts a few more years why replace a system that still works?

    2.Should my proverbial panties be as bunched about the difference between r22 and r410? Most contractors have offered us the choice. We plan to be in the home at least 5 more years, but resale of the home is important.

    3.It’s a two level townhouse with an unfinished basement. Do I really need a variable speed blower? A two-stage furnace?

    4.My wife and I are both reasonable healthy, neither of us have any allergies, we have a standard 1” filter. Again, most contractors have given us a choice. How much do we need a media filter?

    Those are some of my basic questions. The biggest one being whether we should replace the furnace at the same time. If the economy tanks more, could we get a better price if we waited a little while on the furnace?

    Thanks for any advice!

    Oh! One more thing. My dad claims he read about a system that could use r22 or r410. I say no system can do both. The old man’s on drugs, right?

  2. #2
    Join Date
    Aug 2007
    Location
    MN
    Posts
    2,677
    1. replace both(get a system warranty of 10 yrs(if they don't offer it on their system don't buy it)
    2. go 410
    3. variable speed, multi-stage is the only way to go.
    4. 5" media is the best filter to keep your system clean(thats what a filter's main job is for, to keep the equipment clean and operational)

    and last, yes the old man is on drugs!!
    You can't fix stupid

  3. #3
    Join Date
    May 2007
    Location
    DC Metro Area (MD)
    Posts
    3,371
    Quote Originally Posted by cmajerus View Post
    1. replace both(get a system warranty of 10 yrs(if they don't offer it on their system don't buy it)
    2. go 410
    3. variable speed, multi-stage is the only way to go.
    4. 5" media is the best filter to keep your system clean(thats what a filter's main job is for, to keep the equipment clean and operational)

    and last, yes the old man is on drugs!!
    Coming from your friendly neighbor cmajerus (at least he's in MN).

  4. #4
    Join Date
    Jun 2007
    Location
    Round Rock
    Posts
    3,562
    1. Do it all at once if you can afford it. You'll be happier in the long run and cheaper.
    2. 410 definitely. It's already cheaper than R22.
    3. A variable speed furnace is nice if you can afford it as is a 2 stage. Don't overspend your budget to get it. Otherwise it will never work right.
    4. Same with media filter, very nice to have. Don't overspend the budget. Plus keep in mind filters are a lot more expensive to buy once or twice a year than 1" ones are.

  5. #5
    Join Date
    Jun 2008
    Location
    va
    Posts
    800
    Quote Originally Posted by bmathews View Post
    1. Do it all at once if you can afford it. You'll be happier in the long run and cheaper.
    2. 410 definitely. It's already cheaper than R22.
    3. A variable speed furnace is nice if you can afford it as is a 2 stage. Don't overspend your budget to get it. Otherwise it will never work right.
    4. Same with media filter, very nice to have. Don't overspend the budget. Plus keep in mind filters are a lot more expensive to buy once or twice a year than 1" ones are.
    I agree. I believe in keeping it simple. Go with a descent single stage furnace, and regular A/C, or even a heatpump for the duel fuel set-up. If your in the middle of the row of townhouses, you probly won't use as much heating and cooling as a normal house or end townhouse. The heatpump will save big on milder winter days....my 2 cents. Besides, the regular equipment will last just as long as the fancier stuff if put in correctly.

  6. #6
    Join Date
    Oct 2007
    Posts
    226
    Quote Originally Posted by MPLSRYAN View Post
    1.The furnace still works fine. It does have some rust in the system; don’t know how long it’s been rusty. Wish our home inspector had caught that at closing. The big question for us is this: Should we replace the furnace at the same time we replace the AC? Obviously, the contractor will give us a sizable discount to buy together, but if the furnace lasts a few more years why replace a system that still works?
    Does it work fine? Then explain to me why it’s rusted out. Sounds like improper venting and combustion to me. Did anyone bother to perform combustion analysis? Did anyone bother to calculate the ACTUAL efficiency? No, of course they didn’t, why on earth would anyone take critical measurements that can aid you in the decision making process.

    You’re going to want a furnace and an A-coil that are the same size. Here’s where I see a problem. Let’s say the furnace you have now isn’t as wide as the furnace your going to get in a few years, which is very likely. But right now you’re just doing the air conditioner so the contractor will likely buy a coil that’ll fit nicely on the old furnace. Then in a few years when you get a new furnace the coil will be to small and restricting air flow.

    Also, there are savings by doing them together and you’ll get it all done in one day rather than being unconvinced a second time to replace the furnace. Not to mention that the guys that get sent out to install the furnace may do damage to the A/C when they are tearing out the old furnace. They shouldn’t but realistically the installers out there do a lot of things they shouldn’t.


    Quote Originally Posted by MPLSRYAN View Post
    2.Should my proverbial panties be as bunched about the difference between r22 and r410? Most contractors have offered us the choice. We plan to be in the home at least 5 more years, but resale of the home is important.
    Straighten out your panties and go with the 410A, or your gay. 410A is where it’s at brother. The days of R-22 are over and it makes absolutely no sense to buy an R-22 system. Although you may want to hold onto some R-22 since the price is going to continue to double again and again and again.

    Quote Originally Posted by MPLSRYAN View Post
    3.It’s a two level townhouse with an unfinished basement. Do I really need a variable speed blower? A two-stage furnace?
    YES! Pay the extra green for the variable speed and here’s why. Static pressure is a critical factor that will determine how your furnace and air conditioner perform. If you go down to your furnace right now and read the data plate/sticker that is located in the upper compartment, you will see that your furnace has a maximum of .5 inches of water column (.5” w.c.). The same goes for all the multi speed blowers you’ve been thinking of buying, they’re all .5” w.c. Now a variable speed blower is 1 full inch of water column. That’s DOUBLE of what the multi speed blowers are.

    I’d love to go into system design with you but since 95% of the people in this trade can’t even grasp something as simple as static pressure why bother trying to explain it to a home owner. Let me guess, none of the companies that came out to give you an estimate took static pressure readings to diagnose how the new system will perform when connected to your existing duct system? That’s because they’re all to preoccupied with selling boxes with names on them and making false claims about efficiencies that you’ll never see. You can buy a 16 SEER air conditioner and 95% efficient furnace from these clowns and what you’ll end up with after they slap it in is a 8 SEER air conditioner and a 65% efficient furnace, IF YOU’RE LUCKY!

    But maybe I shouldn’t be so hard on them. I mean after all most of them are really nice people. They just haven’t invested the time and money into educating themselves.

    Quote Originally Posted by MPLSRYAN View Post
    4.My wife and I are both reasonable healthy, neither of us have any allergies, we have a standard 1” filter. Again, most contractors have given us a choice. How much do we need a media filter?
    Good air filtration is always a good idea but if it’s going to break the bank this is an area where cuts can be made. Just make sure there’s enough static pressure available for the pressure drop across the air filter you choose.

    Quote Originally Posted by MPLSRYAN View Post
    Those are some of my basic questions. The biggest one being whether we should replace the furnace at the same time. If the economy tanks more, could we get a better price if we waited a little while on the furnace?
    The price of furnaces will continue to rise. Finding someone to put it in dirt cheap is an "epic" mistake. Unless of course they know what they're doing and just don't know their own worth. I see that every once in awhile mostly one man shops. But the bottom line that you'll most likely pay more down the road.


    Quote Originally Posted by MPLSRYAN View Post
    Thanks for any advice!
    You’re welcome.

    Quote Originally Posted by MPLSRYAN View Post
    Oh! One more thing. My dad claims he read about a system that could use r22 or r410. I say no system can do both. The old man’s on drugs, right?
    No idea if your old man is getting high or not. But I can tell you with absolute certainty that R-22 and 410A use different oils which cannot be mixed.

  7. #7
    Join Date
    Dec 2007
    Location
    Cedar Grove, Wi-Sheboygan
    Posts
    1,582
    Here's another reason to go with a VS blower or a 2 maybe a 3 stage furnace. First off most VS blowers today use a ECM motor which when sized properly to your existing duct work will only cost you pennies a day to run 24/7 vs. a PSC motor which is what your furnace you have in your home now probably has and is costly to operate than a new VS blower with a ECM motor. A 2 or 3stage furnace will save you more money over the life of the furnace as in milder weather your frunace will run in low fire about 75 to 80% of the time and when the weather really gets cold or hot then it kicks into the 2nd or 3rd stage's of heat giving you more BTU's to heat your home. Bottom line is buy the best you can afford and just make sure you get a VS minium 2 stage, with a good 4" media will pay for itself in short order with fuel price's on the rise generally within 5 or 6 yrs payback. Also oyu may want to take a look at your insualtion in your home prior to having someone come out to give you estimates and do a load calc to size the equipment will help save you more money in the long run as well, look at your windows, attic insulation, your door's for proper seal as well as windows. All this will keep your operating cost at a minium. Good luck !!! Oh, one more thing check your duct work for sizing as well as seal it up and insulate it will save you there as well, these are things you can do with before the new install or soon after the install of the new equipment.

  8. #8
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    68,120
    Quote Originally Posted by Wild View Post

    YES! Pay the extra green for the variable speed and here’s why. Static pressure is a critical factor that will determine how your furnace and air conditioner perform. If you go down to your furnace right now and read the data plate/sticker that is located in the upper compartment, you will see that your furnace has a maximum of .5 inches of water column (.5” w.c.). The same goes for all the multi speed blowers you’ve been thinking of buying, they’re all .5” w.c. Now a variable speed blower is 1 full inch of water column. That’s DOUBLE of what the multi speed blowers are.
    And what brand has a VS blower with a data plate listing 1" as its rated ESP.

    Vs blowers are rated at .5" the same as most PSC blowers. VS blowers may have CFM ratings up to 1", but that is not the units rated ESP.
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  9. #9
    Join Date
    Jun 2006
    Posts
    294
    quote:
    "My wife and I bought a townhouse in a Minneapolis suburb less than a year ago. We’ve had a lot of fixes in that year, but we now have a problem with the AC. It appears to be leaking refrigerant, and the charge to find and repair the leak was higher than I expected. The house was built in 1995, but a tag on the furnace panel notes that at least the furnace was actually constructed in 1990. Given the age of the system we believe replacing the AC is probably the best choice".

    Why pull the trigger so soon. First off why don't you get another pro (who is less of a salesman and more of a technician) to find the leak or at least give him 1 hour to do so and if he finds it, you are probably good to go for some time. In Minneapolis, youir A/C usage is minimal and so I see no reason why you couldn't get at least 10 more years out of that A/C unit if the leak is repaired. If you opt for any of the high performance furnaces and split A/C, it will take the better part of 7 years for payback; not very cost effective.
    Moreover, if , in the end you opt for changeout, DO NOT HIRE anyone who doesn't, at a minimum, do heating and cooling load calculations and duct analysis of your existing ductwork before sizing the unit.

  10. #10
    Join Date
    Aug 2007
    Location
    MN
    Posts
    2,677
    Quote Originally Posted by sskzekeman View Post
    In Minneapolis, your A/C usage is minimal

    not in my house it's not!! If the heat ain't on the air is! sometimes April to Oct.
    You can't fix stupid

  11. #11
    Join Date
    Dec 2002
    Location
    Rochester, MN
    Posts
    5,304
    Quote Originally Posted by cmajerus View Post
    not in my house it's not!! If the heat ain't on the air is! sometimes April to Oct.
    man, Hate to see your light bill! I turned ours on this afternoon for the first time! You get a call to my parents this afternoon?

  12. #12
    Join Date
    Jun 2008
    Posts
    5

    Smile

    There is much ass-kickage in this thread, thanks one and all for the info.

    I have a follow up or two.

    Our town house has other units on three sides, so we get no cross ventilation at all (no back windows). The bedrooms are also on the 2nd floor, and we have a loft layout with vaulted ceilings. This is nice in the Minnesota winters as we get the heat from the other units, but not terribly pleasant right now. When the AC went out in the first place we called a technician out. I know I can’t quote, but his price to find the leak and repair it was about a third of his price to replace it. The system, as mentioned, is at least 13 years old and is a builder’s grade Tempstar system. The AC is also too small for our house. Having another diagnostic on the system would not be cheap (first technician was going to use a dye kit), and I’m not sure sinking any more money into this machine is a wise investment.

    All 5 contractors took measurements to assess the size of the equipment we would need (and they all ended up with the same size equipment across the board).

    WILD-Does it work fine? Then explain to me why it’s rusted out.

    I’m not an HVAC guy. I turn the thermostat, the house gets warmer=system is working fine…


    WILD-Let me guess, none of the companies that came out to give you an estimate took static pressure readings to diagnose how the new system will perform when connected to your existing duct system?

    I believe this is true, though I’m not sure what that diagnostic would look like, so maybe someone did it. It seems unlikely as no one mentioned it.

    We’ve got a bid we like from a company we like. Basically, we are down to one more decision. He gave us three possible system options. We’ve tossed the cheapest one, because it was a r22 based system, a single stage furnace and not much of a savings.

    The differences between the other two are:
    A variable speed blower
    A 2 stage AC
    A fancy thermostat necessitated by the 2 stage AC
    And a 15 Seer rating against a 13

    The difference in price is about what other companies wanted for the variable speed blower alone. My wife wants to go with the cheaper one. We are going to have finance this regardless (just moved into the house a year ago, and a lot of stuff has had to be fixed), so she thinks we should save the money. The cheaper system still has a two-stage furnace, an r410 based AC and both come with the media filter. They are both Lennox brand systems…if anyone cares.

    Should I try to convince her to go with the more expensive model?

    You guys rock.

  13. #13
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    68,120
    Compare the warranties of teh 2 models.
    Unfortunately, just because something is new. Doesn't mean it won't break down some time. And a good part/labor warranty is nice when it does.

    pennies saved now could be dollars spent later.
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