Buying a house with old furnace

kalpit210

Hi everyone,

I've been in the market to buy a new house for a couple months. I've been lurking on here everytime we get close to buying to house to see what you awesome people have to say about the specific heating/cooling systems the houses have.

The house that we just put an offer in on has a Ruud gas furnace of unknown age. The model number (off my memory, I forgot to take a picture) was UGAC-12KA. Anyone have any idea of how old that could be. I'm aware that it is very difficult to say what year... I'm just trying to get a ballpark 20, 30, 40 years old. The house was built in 1954. I'm also trying to figure out how efficient it is.

Additionally, it has a gas water heater that is 14 years old. We have requested a 1000 dollar credit in our offer for buying/installing a new hot water tank. Since this may be an opportunity to upgrade some of mechanicals, do you have any suggestions on what water tank I should get? My questions specifically: new 40-50 gallon tank vs tankless heater? Is there a way to interface the water heater with the gas furnace to get forced hot air thats humidified or something along those lines? Additionally, is it worth getting the furnace checked out by a heating professional during inspections (if we get the house) to check out its condition and possibly replace it with a more efficienct one? I'm sure the heating company will be biased but I wanted to get your guys' thoughts. I'm a strong believer in "if it aint broken, don't fix it" but want to make sure I'm not loosing out by sticking with a working but older, less efficient furnace

And just to put it in context, I'm a resident at a hospital in new england and will be here for another 5 years after which I'll most likely moving back to CA where I'm originally from. So I'd be interested in making big changes if it helps me save enough money to make the purchase worthwhile in 5-6 years and if it will help with the resale value of the house when I'm ready to move on.

Thanks!
Kal

Steamhead

Is this really a "furnace", blowing air thru ducts, or is it a Boiler that heats water or steam and delivers it thru pipes?

Robert O'Connor_12

The age of the appliance is embedded into the serial number.

unclejohn

I doubt it's in the 30 to 40 year range. Although I replaced a 30+Rheem about 5 years ago. If it's belt driven it's in the 30 to 40 range. Direct drive blower 20 to 30. I would stay away from the tank less heater, doubt you will get a return in 5 years. You may find a date code on the gas valve or control relay normally 4 numbers say 1379 would be thirteenth week of 1979, sometimes they put the year first 7913. If the furnace is old old you are better off replacing it just for piece of mind. Unless you go with something crazy hi eff. you won't get a return but you will be happier, like these people.

Copy and paste.youtube.com/embed/oXvJ8UquYoo

Don_197

Absolutely you should have the furnace inspected by an hvac pro during the process. If this gets coordinated by or through you, make sure the contractor knows this is "inspection prior to the sale of a home" and not just a clean and check. Tell them you want a combustion analysis as well as a CO (carbon Monoxide) test.

kalpit210

Hi all,

Thanks for the quick reply.

Steamhead said:

Is this really a "furnace", blowing air thru ducts, or is it a Boiler that heats water or steam and delivers it thru pipes?

It's a furnace with ducts coming off it. There are vents throughout the house. No pipes, baseboards or radiators in the house.

unclejohn said:

I doubt it's in the 30 to 40 year range. Although I replaced a 30+Rheem about 5 years ago. If it's belt driven it's in the 30 to 40 range.

Copy and paste.youtube.com/embed/oXvJ8UquYoo

Great video . I think I saw a belt when I opened up the last time we were in the house. Unfortunately won't be in the house until inspections now. (They accepted our offer! Just waiting for them to sign the P&S agreement.) But when we are in, I'll try to snap a pic of the serial number and do some investigation.

Don said:

Absolutely you should have the furnace inspected by an hvac pro during the process. If this gets coordinated by or through you, make sure the contractor knows this is "inspection prior to the sale of a home" and not just a clean and check. Tell them you want a combustion analysis as well as a CO (carbon Monoxide) test.

Will do - we will have a hvac person come take a look at it and give us the combustion analysis of the unit and also ask to do a CO test.

If the furnace is 30+ years old and doesn't do too well on the analysis, I'll be back with the results but am leaning towards just replacing it and scoring some of those rebates for high eff furnaces. How much does it cost (ballpark) to buy a new furnace and installing it? The ductwork I'm assuming will stay the same. The a rough calculation for the size of the furnace: the house is 1200 sqft on the first floor and about 600 sq ft in the basement (the ducts have vents in the basement). We most likely will be adding on a bedroom in a year or two (its 2 beds right now, might want a 3rd when we have a kid or two).

As far the water heaters go, would heat pump water tanks be a better alternative to the tankless water heaters? We do get a $400 and $150 rebate for the tankless and heat pump water tanks in RI. Should I just stick to the standard hot water storage tanks?

Thanks for all your help!

unclejohn

That is a toe tapper. I like the standard tanks. We don't discuss pricing on this site, that's so you will do it right and get at least 3 estimates.

John Mills_5

Made in the 1979 to 1982 timeframe.

ProblemSolver

If you are going to add sq ft to the home, you should wait until you begin building so that your new furnace is sized to the new total sq ft.
One efficiency matter that no one talks about is the duct system. With that being said: All the furnace does is heats the air as it passes through the furnace; once the air leaves the furnace - the furnace's job is over with, and the duct system takes over to distribute the air to each room in the house. A poorly designed and balanced duct system WILL diminish the furnace's performance and cause higher gas bills and premature breakdowns. But how would a homeowner know, they have nothing to compare it too. They just think it's the nature of the system - but not so... The duct system can complement or diminish the performance and efficiency of the equipment.

ProblemSolver

If you are going to stay with a standard hot water tank, do some research on what size burner would serve you best, along with what size tank. The standard 50 gal tank has a 40 MBH burner, there were 7 family members in my home and my tank is a 50 gal - 62 MBH burner (fast recovery). Another thing to consider is what shortens a tanks life? If you run it out of hot water completely, that change in temp causes the glass liner (inside) to crack because the glass expands and contracts at a different rate than what the steel tank does.

kalpit210

John mills- you were dead on. 1982. Just had our inspection today. The furnace guy who checked it out located the serial number, which has 1982 in it. He "failed" the furnace. The filter was black. Couple of the vents had black sediment around it. CO2 level was 8.83%, he says 1 and below is normal. No co. He said the heat exchanger had cracked. We will be asking for a credit to replace it.

This brings me to my next question: which heater should I buy? The heating guy recommended high eff guardian. There is one that had modulating 60000 to 120000 btu which would work for our current sq ft (1200 first floor and 500 basement) and also if we add another room of 500 sq ft. Thoughts? Any other recs?

Problem solver - thank you, will have their heating guys check out the ducts too when they install the new furnace.

Thanks guys!

4Johnpipe

Since both pieces of equipment are old and you are in New England try this...
http://www.htproducts.com/phoenixairhandler.html

Paul48

Just a thought......Have the ducts cleaned before you put a new air handler in. You don't want, you or your family breathing the crap that will blow out of that system.

kalpit210

So the seller is only willing to give us a partial credit. We don't want to walk away from a house we really like for a couple thousand dollars...

So I'll probably be buying it myself. Any suggestions for brand? I'm also looking into the HTP Phoenix water heater with the air handler. And downsides to it compared to a standard got sure furnace?

TomS

"CO2 level was 8.83%, he says 1 and below is normal. No co."
How did your pro test the furnace to get these numbers?

ProblemSolver

That Guardian furnace is not a MODULATING furnace; most likely it's a 2 stage furnace - Big difference between the two. Johnson Controls owns Guardian and it's there low end brand. Their other brands are York, Luxaire, and Coleman. These brands have a TRUE MODULATING furnace. The burner has the ability to modulate at 1 BTU increments from 35% fire rate to 100% fire rate, with a variable speed blower motor. There is no other furnace out there that has these operating characteristics. Plus it delivers a comfort level that cannot be matched, even when the duct system is poorly designed. This Modulating furnace is rated at 97.5% eff.

Rich_49

New air handler with the Phoenix is the way to go . No fancy air handlers moving differing amounts of air . CFM is CFM , your house never is more or less CF no matter what the outdoor temp . What good is conditioning some of the air in an attempt for efficiency . use the Phoenix , use the outdoor reset to determine water temp supplied to the coil . This will be the best system you could install without doing major work to the house . In this type of situation you want the water heater sized large enough so that both demands can be met simultaneously . These tanks have a standby loss of about 1/2* an hour so there is no harm done and the extra BTUs won't be used when not needed . You'll just be assured that you'll never run out of hot water .
This is a quality installation method and don't let anyone tell you that it is not . Unless you want to change to a total hydronic system , this is what you want .

Have whoever is gonna install the new AHU seal all the ducts while he is at it and have them cleaned really well

kalpit210

TomS- I apologize I'm not well versed in the equipment but the guy drilled a hole in the flue and inserted the nozzle of something that looked like a long gun into it that seemed to have a probe attached at the end.

I'll look into who in Rhode Island can do it and get some quotes. If you guys have any suggestions for people will do a good job, let me know!

Thanks as usual

RobG

You should contact @Tim McElwain to find a qualified contractor in your area.

ProblemSolver

Rich - CFM is important when trying to control operating time. If you are only adjusting the burner or hydronic temperature and working with a consistent CFM; your control of operating time is limited. The York Modulating Furnace will adjust the burner and blower speed to maintain a long operating cycle at low temperature output, based off its' 3 hour, 3 day, and 30 day memory, plus the discharge temperature. Its' goal is low temp. output at long operating cycle which reduces the number of cycles in a given 24 hour period. I studied the Phoenix system, and I agree with you; it's a nice system when comparing it to other systems within its class. What I don't like about the systems within its class, is the heat loss through the jacket during its off cycle, and having to maintain a temperature for 50 gallons of hot water. Which means to me; even if domestic hot water is "not" being used the system will still fire-up to maintain the domestic water temperature for 50 gallons of storage. Their 1/2 degree - per hour heat loss is shown from the side of the jacket; but 70% of heat loss in any envelope is out the top. Kind-of miss leading. But if the homeowner is more concerned about demand than efficiency, it's an ideal system.

Rich_49

Could it be possible hat when being utilized as a combination appliance the heat loss could be considered much less since it will hardly ever be sitting idle ? 1/2 * per hour is exactly what it is , no misleading what so ever . I have witnessed it .
I can see you may not agree with the fact that a house that is 16,000 cubic feet demands that 16000 cu.ft per hour be conditioned and that is something I cannot get around . The hot air furnace manufacturers can continue in their quest to emulate the efficiency and comfort levels of what a water based system offers .
Here are the simple questions . Does a water heater that is constantly flowing water to a coil at temps based on outdoor reset where the system is tightly matched to the actual heat loss really have a standby loss ?
Will air side folks ever realize that air movement makes human beings lose their natural body heat ?
Does it cost more to run gas pipe to 2 appliances ?
Is it conducive to efficiency to have 2 gas burning appliances and more envelope penetrations ?
Gadgets break , why not keep them to a minimum ?
Why in the hell is a furnace using a memory instead of actual conditions at present ? Who the hell wants to pay for that extra , useless technology in a box that burns air ?

ProblemSolver

Rich, everything you said has a lot of truth to it; but that is only because the majority of forced air designers and installers have no clue how a forced air duct system works. Plus, you just made a comment on a furnace you have no education on. The memory is so the furnace can learn what the demand of the home is based off its’ heat loss, and then adjust itself to maintain a mean temperature. It doesn’t raise the temperature then wait for it to drop; it maintains the temperature through learning. And 90% of the time, the homeowner doesn’t even know the furnace is running because it’s operating on low fire and a low variable blower speed. The “hot air furnaces” you described are all the other furnaces that are out there. Also, forced air furnaces “do not” remove heat from people by way of air; it’s the temperature differences within a room trying to equalize, called “stratification”. This stratification causes evaporation of the moisture on the surface of your skin; and as you should know, evaporation of moisture on any surface will cause that surface to drop in temperature. Therefore, it is not the temperature in the room that is causing “winter chill”, nor is it the movement of air causing “winter chill”, it’s the temperature differences within the space causing evaporation off the surface of the skin that creates “winter chill”. Another thing, your CFM description is exactly what every other HVAC tech pays attention to, and that’s it! What you all are missing in your equation is velocity. If you look at a ductulator; a 2x4 stud space will provide about 200 CFM of air delivery, based off a certain velocity and noise criteria. But that stud space is very capable of delivering 600 CFM at a higher velocity. If you don’t balance your duct system based on CFM “and velocity” the duct system will never deliver comfort and efficiency. So you see, you couldn’t get around the CFM thing because you didn’t know enough, but don’t feel bad, 90 + percent of this residential HVAC trade doesn’t apply velocity in their equations of building a duct system. And velocity is balanced based of the science that high pressure always goes to low pressure. The only thing I left out of this is how to control velocity to get the CFM that is desired; but that’s another conversation. Please don’t misunderstand me, I am 100% with you; I would rather have a hot water boiler system in my home for all the reasons you mentioned, and then some. But 60 to 70% of my customers have forced air; therefore I must know as much as I can about forced air so I can provide the best there is to my customers.

Rich_49

All of your customers also probably need a water heater so do them a favor and use it to provide their heat also . The water heater I spoke about is made exactly for this purpose .
What you don't understand is that T air is not a proxy for thermal comfort my friend . I design and install healthy comfort systems . Let me explain , because you're almost there and possibly may be in the top 15 percentile of designers .
Never should you install systems using the framing as a component or part of any system . If it is a ducted system , use ductwork , NEVER the building framing and structure .
It is impossible to predict weather patterns and temps based on what happened the last 3 , 5 , 7 10 , 30 days . This is a silly attempt to keep having something to compare with better systems and keep cash flowing for the FHA industry .
there are 4 means of heat transfer , conduction , evaporation , convection and radiation .
I have been in many houses with PROPERLY designed and installed FHA systems and I can tell you that you cannot load temperature into building mass using FHA . I made the statement I made based on Comfort , fuel usage , economy of operation and LCCA .
It is more efficient to heat water than air which is what happens in a furnace of any sort as you are aware . From an efficiency standpoint , using a system that is already required and lessening the penalties of loss is an often overlooked strategy . It lessens the amount of fuel within the building envelope , desirable . It lessens first cost . It is capable of matching the load better at all times . My advice to the air side of the heating industry is stop attempting to do the impossible , focus on building better air handlers because FHA is not going to go away and use water heated by another source that can be delivered in exact amounts required using simple sensors as opposed to logarithmic information programmed by folks who cannot predict weather . Learn how to design better . As you stated design the ductwork correctly so you never need to exceed air speed to a point above where folks have to hear it .
The poor public is having this garbage shoved down their throat because it is lower first cost . You , my friend are an anomaly, fact is forced air designers and installers that have a clue are less likely than a water side guy who knows what he is doing . I keep waiting for some truth out of the FHA camp but rarely hear any .
In case you never looked at the BIG PICTURE for retrofit and new construction let me clear up a few things . An entire industry has been formed almost solely due to the effects that ducted systems have created . We now insulate steep pitched roofs that are roughly 3xs in area than the ceiling . WHY ? Because we have to bring garbage inside the thermal envelope . WHY ? Because ducts are leaky , can only be installed most times in what we used to call an attic or a basement . Unsightly soffits and interior details must often be added and firestopped to hide this ducting . In many jurisdictions it requires dampers that will close in case of fire . It transports air from room to room and area to area along with all types of nasty stuff that may be in that air causing the spread of illness and odor and moisture . These systems cannot be zoned because coils and how they respond do not react well to this . Keep it up FHA industry , soon you will be as costly as wet systems if you are not already based on the mentioned overlooked costs associated with using this INEXPENSIVE technology . And how or can you achieve this

http://www.greenbuildingadvisor.com/articles/dept/building-science/should-doe-increase-furnace-efficiency-standards

As houses get tighter and tighter and require ventilation will FHA continue to be less expensive . This industry has always relaxed with the fact that it can provide heating and cooling and using wet systems required a ducted system anyway . Can that survival model actually last as we have now shown we can provide both heating and cooling with radiant systems and DOAS for these tighter houses . I am starting to show builders and homeowners the hidden math and science behind this and the lie can't last forever .
I tried to give good sound advise and somehow you took it out of context . A coil is pretty damned inexpensive and with the proper math applied the whole building could benefit on 2 different fronts in efficiency but you overlooked that .
Operating time you mentioned is interesting also .I am interested in what you think is a more efficient run time , always on or on / off ? Because with ODR control and constant circulation we could almost always be running at very low velocities with very low water temps .

Looking forward to your responses . I never have done this before but for your knowledge I will now . Rich McGrath : LEED AP B,D & C , LEED GA , BPI building analyst , Rutgers University Certificate in Green Technology (Rutgers advanced technology ext.).
Just so you understand that I get it . I don't design ducted systems but understand them and building science completely . This is my designers work . The house has radiant floors and is 3,800+ sq ft . I work as part of a team usually whenever ducted stuff is to be part of the HVAC scheme .

ProblemSolver

Okay; you're in a totally different environment than I am, with very different rules and design options. But your last thread was very impressive and extremely detailed. We are only required to get that detailed in the commercial, industrial, and institutional part of our trade. Residential and some light commercial designs do not require such detail to get a permit; in fact, we are not required to do a manual J, only a duct plan to get our permits. I believe we are on the same page when it comes to providing our customers with the very best; but in my case, most of the consumers are not as interested in their HVAC system as they are in their Kitchen Cabinets. This is very frustrating for me, as I am sure it is for you. So I do the best I can with what they are willing to pay for. I do occasionally pickup a customer that is totally involved with getting the best HVAC systems their money can buy. That is when I shine and radiant is what gets installed with IDHW and a Unico cooling system with a hot water coil, in most cases. Humidity control is not a problem here in Michigan, so a standard cooling design is all that is needed.

The balancing of the duct system: Forced air is NOT about defeating a temperature within the building, it's 100% about changing the air. Remove the undesirable air from a room and replace it with the newly conditioned air; this is how forced air systems are suppose to work. Therefore, the return air opening in every room is the most important part of a duct design. If you don't remove the undesirable air (negative pressure), then the newly conditioned air (positive pressure) will not come into the room. Therefore, you must balance how the return air trunk draws air from each opening. In doing so, this helps balance the supply air that enters each room. Darn near every Heating company in my area, only pays attention to the supply air and if the second floor bedrooms are not cooling, these companies install fan boosters in the 2nd floor supply runs, thinking that will put more cool air into the rooms. WHY? - I have no idea how they justify such a method.

How the blower finds the air it needs: The blower will draw as much air as it can from the closest opening first, then what it can not get from that opening, it will draw all it can from the next closest opening; and so-on down the line. We use the joist space as our return air runs - off the trunk line - and all these Heating companies cut large holes in the return trunks because they believe the stud space (3.5" x 14") will restrict the air draw to 200 CFM. Because of this, the blower typically gets all the air it needs from the 1st floor openings and has no need to draw from the - further - 2nd floor openings. Remember what I said, "you must remove the undesirable air from the room, so that the newly conditioned air can enter the room." So, the rooms that are uncomfortable will also be the rooms that lack return air. What I do is restrict the amount of air (at the trunk) the blower can draw from the 1st floor openings; thus, forcing the blower to draw from the 2nd floor openings. Once this is accomplished, the efficiency of the home to retain its' heat is improved because stratification is eliminated and therefore ex-filtration is greatly reduced, especially with the York Modulating Furnace that operates at a lower out-put temperature and longer operating cycle - than all the other furnaces out there.

I am not challenging your systems with my forced air system; I would prefer doing nothing but Hydronic (but no baseboard elements) because of zoning, temperature control, and the value of radiant . But the consumer has control over that decision, not me; and the cost of a furnace is much more appealing to them than a boiler and/or air handler. So like I said before, I must offer them the best that they are willing to pay for; and in some cases, they want less than that! Which I suggest to them to hire someone else because I will not knowingly do hack work.

Rich_49

I was never challenging your system either , I get it . It is what it is . I merely suggested using a highly efficient water heater to perform the task of providing the heat also .
What you don't understand is that the job details given are in fact for a home in Ann Arbor my friend . That design was performed by someone whom I work with when the project requires that . He is quite possibly one of the best in the country , I can verify that and so can the 3 or more building science TITANS that send work his way .

What I was telling you that flew over your head in your attempt to sound intelligent was that you do not need to use more expensive forced air stuff with all matter of controls and techy trash . Use a simple air handler , single speed fan , size the ducts correctly and run it off the water heater . At the end of the day that system is less first cost and you have made the home safer with less flammable and explosive stuff inside the envelope .
As I said ALL the air must be conditioned ALL the TIME . Whether it be to remove latent take care of sensible or heat .
I will say that I am glad to see someone that knows how to do ducted systems and that will decline putting in COMPLETE trash based on a fantasy budget someone has . Your description of proper system design is pretty basic and unfortunately just like in our wet side very few know how to do it anywhere near properly . You may be the exception as opposed to the rule but what you describe should not be special , it is how it is supposed to be done , A BALANCED SYSTEM should not be exceptional but we all know it is .
I operate in the same world as you and the things we designed for this Ann Arbor house were not required by the AHJ for permitting or any other reason . It is just what we would prefer to work on , a healthy , tight , energy efficient home or building . Ann Arbor and a 705.00 annual gas usage and almost nill electric . In my opinion it is all we should be building . Not because we have an energy crisis but because we have a consumption crisis .
Maybe you could send me your information and the next time we design in your area we'll see if you'd like to install .

ProblemSolver

You know Rich, the more I thought about it, the more sense it made. A furnace with a modulating burner/variable blower - compared to a boiler with an outdoor reset & an air handler. What are the options? Furnace - modulating burner/variable blower. Boiler with Air Handler - outdoor reset, ECM motor, 5 times more domestic hot water, zone control using forced air plus, radiant / steel radiators / basement heat on its own / garage heater / floor warming...
I guess I was defending an old mind-set, but at the same time I am fully aware of the options with boiler heat because I have installed quite a few of them and I would rather stick with boilers over furnaces. Right now, I have 5 jobs running, and all of them are boiler jobs; 2 steam systems, and 2 boiler / baseboard re-pipes, and one complete radiant floor system with a furnace backup coupled with A/C - spiral duct, in a commercial building being converted to a residence in Dearborn. And I am bidding on a new 3,400 sq. ft. home - I will have to see if they will be interested in the boiler/air handler option instead of a furnace. I will have to give that one a lot of thought in how to sell it.

Rich_49

Not a boiler Problem Solver , A WATER HEATER , every house has one .

4Johnpipe

This is what Rich is talking about...
http://www.htproducts.com/phoenixairhandler.html

ProblemSolver

OK, I took another look at it. No ****, it's a Hot Water Tank. Thought it was a combo unit. So they run domestic water through the air handler coil? Nothing like that around here. I'm going to have to chew on this for a while, but I like the concept. I thought of doing something like that, using toe-kick heaters to heat my basement. My five kids are now out on their own, but I built 2 bedrooms in the basement and moved 2 of the kids down there. I didn't build the system because I didn't think it was legal to run domestic hot water through a copper heating element without a plate heat exchanger.

Rich_49

Just make sure whatever circ you use exercises at least once a day for a couple minutes . There is no threat of an inactive area generating anything nasty then .

ProblemSolver

Good point!