Furnace questions please

12 Replies

Furnace experts - please help...

I am looking for replace furnace for a rental unit soon... It is for a 2/2 condo that is currently renting $4500 a month...

1. what brand is good

2. How much BTU is good

3. what is the cost?

Thank you in advance for your knowledge /expertise... thank you


I personally like Lennox. They offer 10 year warranty on parts but labor will come out of your pocket and that's something you can work out with an HVAC company. Companies offer labor warranty which I would recommend getting since labor usually costs more than the part itself.
Your current unit should have the right size installed already. The tonnage of the unit is based off the size of the area being covered. For 2 beds 2 bath I'm assuming around a 1.5 or 2 ton unit (12,000 or 24,000 BTUs)
The prices vary on the efficiency of the unit. You get what you pay for but if you're looking for cheapest you're looking at the least $3,000-$4,000 but I'm not completely sure if the prices get higher in bigger cities. I'm in a rural university city and that's the low prices here.
All the information you're looking for can be explained to you by a salesman from an HVAC company. Majority of companies go out and give information of systems that best suite your wants and needs as well as price quotes at no charge to you which is not bad. I hope some of this information was somewhat helpful. Best of luck to you!


@Diane G.

I have been installing and servicing HVAC equipment for 40 years now and I can say, based on experience, there is very little difference between brands. They all have good points and bad points but there is no bright shining star that stands out above the rest. The biggest factor by far in how reliable a piece of equipment will be is the installing contractor. I have seen a lot of good equipment installed poorly that has failed prematurely. Duct systems, piping systems, flues, combustion air inlets and maintenance can be much more important than furnace brand. Finding a quality contractor is key but unfortunately, for investment purposes, he will probably not be the cheapest.

BTU output of the furnace should be determined by your contractor. A heat loss calculation of the building should be performed to determine the proper unit size. The days of taking a guess based on square footage of the space are over. Most towns will require a copy of the calculations when issuing permits.

Costs will vary depending on what is required. If it’s just the furnace that needs to be replaced that will obviously be less expensive than if you need duct modifications or air conditioning replacement as well. One hint to keep your costs down however, stay with standard efficiency equipment. The extra cost of purchasing and installing high efficiency equipment is rarely, if ever, regained by the fuel cost savings. The number of years needed to break even is usually longer than the equipment will last. Additionally, the cost of repair parts for high efficiency equipment can sometimes run as much as three times the cost of standard efficiency parts. One service call for emergency repair could wipe out any energy cost savings, present and future.

@Tom W. Thank you for spending your time and give me the detailed knowledge.... I soooo appreciate it... very helpful

I tend to side with Tom in that the brand is not the deal-breaker. Trane (Nothing stops a trane) cost more than a Goodman, even for replacement parts that are fairly generic like flame sensors. It is true that the Trane is superior quality, but they fail too. One of my tenant a few years back, ran the AC/heat/fan almost continuously 365days a year even when she is at work, due to her lovely cats. That unit deteriorated rapidly developed a cracked condenser not worth fixing. Versus the other side of the duplex where frugal family hardly used the system, almost no wear. So I wouldn't spend a lot more on a brand just for slightly higher reliability. Too many random variables.

You'd be better off finding a reliable, honest repairman. Many so called hvac problems are caused by minor, small cost items or just adjustment. Too many techs replace a motor when a $20 cap is bad.

im also an HVAC by trade. I see little to no difference between furnace manufacturers (many/most of the internals are the same between brands) as for sizing (btuh's) you really should have a pro take a look at the place. some rules of thumb could get you close based on square footage, ac or no ac ductwork.... but you would definately be better server to have someone run load calcs.

Don't DIY sizing by using rule-of-thumb. Most novice guess then they think, "I'll just make get the  bigger one to be safe. BAD (cost, noise, comfort, energy).  My duplex only needed 3 ton, but pre owner installed 5 tons. :-(

Ok , I will ask . You say furnace . Now is it a natural gas furnace , propane , heat pump or heating oil ?  

Thank you every one for helping... I will find a reliable contract to do the replacement...

I don’t know if it is gas or propane etc

I just know that it is 40 years old... Lol

@Tom W. and all you experts - my current furnace, I was told is more than 30 years old but has been running fine... Should I replace it this season, or should I wait for it to break down to do anything?  Thanks

It is gas, in Bay Area.

It it works, keep it. They normally do not break down easily.

Have it serviced.

The cost for HVAc contractors varies by 2-4 fold in Bay Area. Costco subcontractors quoted me $8000 for a Lennox. Another company did the work for $2500-$3000.

It also varies whether you pull the permit or not. If you do, they may require checking your existing ductwork for air tightness.

@ Diane G.

30 years for a warm air furnace is old. If it's a hot water boiler it's still up there but boilers tend to last longer.

The question about whether to replace now or wait another season is always a tough one. Heating systems never fail when they aren't needed. They always go when needed most because that's when they are being pushed the hardest. I typically advise customers to be proactive and replace before the equipment fails. This gives you the ability to shop around for the best contractor and best price. If you wait until the equipment fails and replace under emergency conditions your options are cut drastically and you will almost certainly pay a higher price.

I agree 100% with @Tom W. I recommend getting it done before you have to. This buys you time to shop around and make informed decisions. I dont recall if you stated where the property is, but a no heat call here in Minnesota in the middle of winter can be a big deal giving an investor very little time to react.

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