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Thread: HVAC contractors

  1. #41
    Senior Member jp1's Avatar
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    Had an hvac guy inspect our furnace today. It's become clear over the past couple of weeks, with temperatures down in the 30's, that we will need the furnace more than we thought. He glanced at the furnace and said "Wow! That's pretty old." After doing various tests on it he pronounced it in fine working function but he thinks we'll want to replace it relatively soon because it will just start breaking. and breaking and breaking and breaking... I also asked him to look over our duct work. It's a mess. Half of it is up in our attic for no logical reason and hidden behind drywall. From what he could see it's obviously leaky. He also had good thoughts on whether we would want to do central a/c (it's ready but he recommended doing a pressure test of the line. Since the never used a/c line is 43 years old if it won't hold pressure we would need to start from scratch, which would include ripping out drywall so that we could install a new one.)

  2. #42
    Senior Member razz's Avatar
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    After 43 years of technological progress, the savings on energy for heat or cool will be considerable with a new system.
    Last edited by razz; 11-11-20 at 9:01am. Reason: Missing some words
    As Cicero said, “Gratitude is not only the greatest of virtues, but the parent of all the others.”

  3. #43
    Senior Member jp1's Avatar
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    Quote Originally Posted by razz View Post
    After 43 years of technological progress, the savings on energy for heat or cool will be considerable with a new system.
    Indeed. Our first combined gas/electric bill was twice what we were paying in our old apartment. I assume that’s mostly because we now have an electric stove and dryer and electricity is pricey here. But once we add in regular furnace usage of an old furnace that will only get worse. Upgrading to a new more efficient furnace will likely help but I suspect that fixing the leaky ductwork will help even more.

  4. #44
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    If you go the minisplit route, will the ductwork be relevant?

  5. #45
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    Oh great question on the mini split - my son talks about this as a great option when he repairs things. I think he said mini split does not require ductwork.

  6. #46
    Senior Member jp1's Avatar
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    Yeah, a mini split might be the right option for us. Obviously we haven't been here for a full summer yet so right now we're kind of planning to just live here and see how things go. In the spring we're most likely going to get a two hose portable a/c to use in the upstairs during the day when I'm working and try to continue doing the "open everything up overnight, close it down in the morning" routine to avoid going full on air conditioner mode. If it turns out that we really do need more a/c than that a mini split probably makes sense because the reality is that the downstairs just doesn't need much cooling. Even on days that it got to 100 outside it only got to 73 downstairs by late afternoon. During the long days of summer it may get a few degrees warmer. But if we have a/c upstairs, whether a portable unit or a mini split, some of the cool will spill down the stairs to make it fine down there as well.

    Replacing the ducts is a completely different issue. And also one that I want to wait on until we've lived here a while. My guess (fear) is that a lot of heat is getting delivered to our attic and lost. My other guess is that we don't really need a lot of heat delivered upstairs. Time (and a cold gloomy winter if we have one this year) may change my mind on that. For the time being I've actually bought two magnetic vent blockers for the secondary bedrooms. (my work office and my personal den). If we go through the whole winter without me removing them to let heat in the rooms I will be inclined to have the hvac guy just remove the ducts to those rooms entirely when they replace the furnace.

  7. #47
    Senior Member jp1's Avatar
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    And now it's two years later and today I scheduled our hvac guy to come out and do a safety inspection of our now 45 year old gas furnace... In the interim we've lived through two years in this house and learned a few things.

    One, we need far more heat than we expected. In winter I've got the thermostat set to 64 overnight and during the day, and 68 from 5:30-7:30am and from 5pm-7pm. That warms things up enough that SO doesn't grumble when showering and getting ready for work and again when we're watching tv/eating dinner in the evening. The rest of the day and overnight the temperature inside gradually falls but it wouldn't matter whether we have the thermostat at 64 or 40, it pretty much only runs during the four hours/day it's set at 68.

    Second, we need central a/c. We had a six day heat wave over labor day where it got up to 110 everyday and only down to 60 overnight and it was still over 80 outside at bedtime. I bought one of those portable a/c units (12,000 btu) I mentioned upthread and that's fine for keeping my office tolerable on hot days (office faces SW so gets major afternoon sun) but it's not enough to keep the whole house livable during a major heatwave. And whenever we go to sell this place having central a/c will be a major selling point.

    Third, when talking to hvac guy today about replacing everything he suggested a hybrid system that is both high efficiency heat pump and gas furnace. With the rebates for converting to electric heat that are available in California this option wouldn't cost much more than a new gas furnace and standard central a/c unit. The idea is that we could then use the gas furnace on cold mornings when heat pumps are less efficient and then the heat pump in the afternoons when outside temps are warm enough to make that the more economical option. (he suggested that it would actually make more sense economically to schedule the afternoon reheat of the house to start a couple hours earlier when outside temps are warmer).

    Fourth, I don't know if I mentioned this in a different thread, but at some point not too long after we moved in one of our neighbors shared with us that the original owner of our townhouse installed a pot grow room in the attic. He screwed with the furnace ducts to get all the heat up there which is why our ductwork is such a mess. Whatever decision we make about our new hvac system replacing the ductwork completely will be a part of it. Hvac guy says that with modern, insulated ductwork and modern blowers the heat/cool will get distributed much more efficiently and quietly. If nothing else our current blower uses probably 150 watts of electricity compared to 15-20 watts for modern blowers.

    I've typed all of this to ask, has anyone here switched from a gas furnace to a heat pump? If you have do you have details about how much gas you were using compared to the amount of kwh's the heat pump used? Our natural gas rates are comparable to the rest of the country but our electric rates are absurdly expensive ($.31/kwh) so I'm dubious that a heat pump will be the most logical choice economically. I suppose if we can install a hybrid system without dropping much money up front we can do a comparison and stop using the heat pump if it doesn't make sense, but I'd like to try and get some sort of real world examples ahead of time if possible.

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