How much does a whole HVAC system cost?

What a whole system costs

This Old House gives $5,000 to $12,500 for a standard-efficiency air conditioner and furnace with a simple duct layout, and says premium-efficiency equipment in larger homes can exceed $22,000.

Their prices for the pieces, installed and excluding ductwork:

New ductwork adds $1,000 to $2,700.

The same machines, priced by the other publisher

Fixr is higher on every line, and markedly so on cooling. Our arithmetic, marked as ours: take Fixr's two averages for the pair this page is about, $8,750 for the air conditioner and $4,800 for the furnace, and you get $13,550 for a system This Old House tops out at $12,500.

So the two publishers do not agree on the whole-system figure, and the disagreement comes almost entirely from the cooling side.

And This Old House does not agree with itself

This is the part worth pausing on.

Those two ranges overlap only between $6,345 and $8,000. The second page's average, $8,460, is above the first page's entire range.

Our central air page already notes that the air conditioner guide carries a third figure, $16,759, at the top of the same page. That makes three different This Old House numbers for an air conditioner, across two pages.

Our reading, marked as ours. Where a publisher's own pages disagree, we take the one that agrees with an independent source. Fixr puts central AC at an $8,750 average and This Old House's air conditioner guide at $8,460, which is $290 apart. The $4,000 to $8,000 on the installation guide agrees with nothing. We would plan the cooling half at around $8,500, not $6,000.

What that makes a realistic whole system

Our addition, marked as ours, and built only from figures that two publishers support:

That is above This Old House's headline range for a whole system, and we would rather tell you that than reproduce a figure our own comparison does not support. If your quote lands between $5,000 and $8,000 for both machines, that is cheap rather than normal, and worth asking about: standard efficiency, smaller capacity, or existing ducts in good order are all legitimate reasons.

The alternative that replaces both

A heat pump heats and cools from one machine, so it is not a third item on this list, it is a replacement for the first two. This Old House prices it at $4,200 to $7,600 on this guide and an $8,042 average on its own heat pump page, which our heat pump page sets out alongside Fixr's $8,350.

Our arithmetic: at roughly $8,000 to $8,350 for a heat pump against roughly $13,300 for a furnace and air conditioner, the heat pump is the cheaper way to get both functions, before any rebate. Whether it suits your climate is the other half of that decision, and the heat pump page covers it.

Before you sign a whole-system quote

1. Get the two machines priced separately. A single number for "HVAC" hides which half is expensive.
2. Ask whether ductwork is in it. At $1,000 to $2,700 it is the line most often assumed rather than quoted.
3. Ask the efficiency rating. It is the difference between This Old House's $12,500 and their $22,000.
4. Price a heat pump as a third quote, even if you did not plan to. It is one machine instead of two.

Once it is in, the running cost is the maintenance, and the thing that goes wrong first is usually on the cooling side: see our AC repair page. On the heating side the two complaints we see most are covered on our cold air page and our furnace will not turn on page. If the heating half of the quote is a furnace, our gas, electric, propane and oil pages price each fuel on its own. A house with no usable ducts may be better served without them at all, which our mini split vs central air page works through. A hydronic house replaces the heating half differently, on our boiler replacement page, and distributes it differently again if the heat comes through the floor, which our radiant floor heating page prices.