Find out how long a typical HVAC unit lasts. Learn what to consider when shopping for a new HVAC system. Get tips on choosing an HVAC system that is energy efficient and the right size to keep your home comfortably cool in the summer and warm in the winter.
LESLIE: If you’re sweating in the summer and shivering in the winter, it might be time to replace your HVAC system.
TOM: That’s right. But with all the options, trying to figure out just what to buy can make you sweat just as much. For tips on how to shop for a new HVAC system, we’re joined by Richard Trethewey , the plumbing-and-heating expert for TV’s This Old House .
RICHARD: Nice to be here again.
TOM: So, how long does a typical HVAC system  last?
RICHARD: Well, it can last a long time with proper maintenance. I think it’s one of the few appliances on the planet that people expect it to last forever. You know, we’ll talk to people who’ll say, “How long has your heating system been there?” They go, “Oh, it’s pretty new. Yeah, we put it in when Suzy was born.” “How’s old Suzy?” “Well, she’s 50.”
And so people expect them to last a long time. Most of the systems, you can expect, I think, 15 to 20 years at least. What we’ve seen, though, in the last 20 to 25 years is the efficiencies on the equipment have gotten so much better than they were in the 80s. There’s been such a quantum leap with all these condensing appliances and these super-efficient pieces that even if the system was working fine, people should be thinking about changing it from the financial side of it.
Because if I can save 25 or 30 percent on my fuel bill – there’s even more that we can save on many of them – think about if it cost you 10,000 bucks.
RICHARD: Where would you put $10,000 nowadays and get any return on it? Would you put it in a passbook savings …?
LESLIE: Why do I feel like you’re talking about my house, you’re talking to me?
RICHARD: Yeah. You’re …
LESLIE: My 42-year-old boiler and my $10,000 new boiler/heating system, thank you so much.
RICHARD: Right. But I think most people are not explaining to the consumer the whole financial side of it, that there’s no question fuel is going to keep going up. If I can save 25 percent now on what my fixed costs are – that are no longer fixed, that are going to go up – there’s no better investment right now than to put better heating equipment into a building. And people just ignore it because it’s the dirty, dark part of their building; they don’t want to think about it.
TOM: Well, let’s say we’re going to replace it. What’s the most important thing to consider? I mean one of the things that I see a lot is that people think bigger is always better when it comes to HVAC systems , like other things.
RICHARD: Yep, yep.
TOM: But isn’t it more important to size the unit to match perfectly what the actual heat loss of the house is?
RICHARD: That is – the biggest crisis in the whole heating-and-cooling industry is oversizing. And the homeowner is an unindicted co-conspirator on this. If you’re talking about – people measure the cooling systems in terms of tonnage.
RICHARD: And they’ll say to somebody, “Alright. How much for a 2-ton system?” And he’ll give a number and they’ll say, “Well, how much for a 3-ton?” And they’ll say, “Oh, it’s only that much more for the extra ton.”
LESLIE: “Well, might as well get the 3-ton.”
RICHARD: Right. And they might have a ton-and-a-half or less in load. And so, really, this oversizing leads to so many issues. Uncomfortable in the house, for one thing, but also, if you have any mechanical device and you make it come on and come off every nine minutes, it really wants to be on for a long time and off for a long time. And that’s what we don’t see in this country because we oversize so much.
TOM: Right. So it cycles. It comes on, drops the temperature, goes off.
RICHARD: It cycles like crazy. Yep. On and off, on and off, on and off all day long.
RICHARD: And if you did that to your automobile or your lawnmower – turn it on and off every 20 minutes – it would be – it would fail in a relatively short period of time and it wouldn’t be efficient.
LESLIE: And will that cost more to operate?
TOM: So the solution is to do what is known as a heat-load analysis. So talk about that.
RICHARD: Yeah. I think when you’re talking about an HVAC system, it is a system that is designed and installed by a professional. You should shop the contractor first; you really should. You should find somebody in your local market, through word of mouth or otherwise, that has been in the game for a while and knows what they’re talking about. That person then has an obligation to himself and to you to size this thing perfectly. And what we need is to have – is the right-size unit  for the coldest day of the year for the heating side and for the hottest day of the year on the cooling side.
Now, everybody, you might do a thing called a heat loss. And if it came out – historically, in this country, if you came out with 100,000 heat loss, this wholesale supplier and the contractor, historically, would put in 150,000 – 50 percent extra size. And then always with a wink and a nudge say, “Oh, that’s just in case you add onto the building.” But that means you would – it would be like having a V12 engine in a little Volkswagen, so it’s literally just on and off, on and off. And that’s really what we’ve got to fight against.
If we’ve done our job in the heating industry, on the coldest day of the year, the heating boiler or furnace would never shut off. It would just be on to satisfy. And then in the milder times of the winter – now, think about it, most of the heating season is not that cold day you remember. It’s the spring and the fall and it’s about 70 percent of the heating season you could have heated with less furnace or boiler power. You could have heated with less gas input. You could have heated with lower water temperatures. And that’s where the savings come in, in those long spring and falls where you don’t have this oversized thing on and off.
TOM: Now, does the length of time that you’re going to live in the house – should that play any part of the decision as to whether or not you should change the system or not? You want to be there long enough to get the benefit?
RICHARD: Everybody says they’re going to move and then you still see them 25 years later still there.
LESLIE: Same house.
RICHARD: And they rationalize the way they want to rationalize it. And so, I think people have to understand it from the investment thing that I talked about just a minute ago and to say, “I know the fuel is going to go up. How do I hedge against fuel going up? Well, I jump into the game now to cut my fuel bill. It’s only going to save me more when fuel goes up. But it’s not going to be the payback. I’m only going to be here a year.”
You know, there’s something very interesting in Germany I’ve seen recently, which is a thing called an “energy pass.” And it is for any home or any apartment. You, before you rent it or buy it, you know exactly what that building spent in fuel to heat it. Now, imagine that metric if we did that in this country.
RICHARD: Now, you would buy a house and it would say, “Oh, this has got this rating.” And now it would be more valuable to you because the cost to operate it would be less. And in Europe, we see it. When you are going to rent something, if it’s got a high energy pass where it’s not efficient, the landlord can get less rent. And so now it’s a market driver to force people to save energy .
And I think we may never get to it in this country but it’s an interesting idea to think about. And we have 5 percent of the world’s population and we use 25 percent of the world’s energy. We use two times more per capita than anybody else in this planet (inaudible at 0:26:31).
TOM: Well, that’s why if you’re buying a house today, it definitely pays to ask for a year’s worth of utility bills.
LESLIE: Oh, absolutely.
RICHARD: Yes. Yeah, yeah.
LESLIE: And I even have to say, when we made the changes to our heating system  this year, I immediately thought, “Even if we move next year, from a resale-value situation, somebody is going to look at our brand-new, three-zoned heating system and say, ‘Wow, this is ready to go. I don’t have to make that change.’”
RICHARD: Yeah. Yes. That’s right. That’s right. That’s right.
LESLIE: And even when I look at listings, I’m like, “Ooh. A 30-year-old oil heater.”
RICHARD: Yeah. Yep, yep.
LESLIE: I’m like, “Hmm. Not so desirable.”
RICHARD: I’ve often wished that we could actually put our heating equipment out on the driveway and our cars down in the basement. Because then people would pay for …
TOM: More attention to it.
RICHARD: More attention to it.
LESLIE: Well, if everybody created plumbing-and-heating systems, Richard, the way that you do so beautifully, that captivates both Tom and myself into these bowels of the homes that you guys work on, then absolutely I would say put them right in the front of the house.
RICHARD: Yeah. So …
TOM: Alright. Great advice. Richard Trethewey, the plumbing-and-heating expert on TV’s This Old House, thanks so much for stopping by The Money Pit.
RICHARD: Always great to see you guys.
LESLIE: Alright. You can catch the current season of This Old House and Ask This Old House on PBS. For local listings and step-by-step videos of many common home improvement projects, visit ThisOldHouse.com.