Heating & Cooling

This is the newest section on the site, opened on 17 October 2026. It works the way the rest of the site does: every figure names the guide it came from and the date that guide was updated, and where sources disagree we show the disagreement instead of splitting the difference.

The thirty-five questions so far

Whole systems

Page	The short answer	What it adds
Furnace replacement	about $4,800	three averages within $57, and the sizing table two publishers share that turns out to be plain arithmetic
Gas furnaces	about $6,000	the furnace itself is under a third of the bill, which is why two quotes for one model differ by thousands
Electric furnaces	about $2,400	the cheapest to buy, and why nearly 100% efficient says nothing about what it costs to run
Propane furnaces	about $4,800	the widest spread of any fuel, and it is the tank and the lines rather than the furnace
Oil furnaces	about $4,900	one publisher's average sits below the floor two others share, and the tank may be the whole difference
Boiler replacement	about $6,100	headline ranges $1,500 apart at both ends, and a sized job the two publishers quote within $100 of each other
Central air conditioning	about $8,500	two publishers within $290, and the $16,759 one of them prints at the top of the same page
Heat pumps	about $8,000	three machines sold under one word, and what the payback actually works out to
Mini splits	about $3,000 to $6,357	one publisher prices the same machine on two of its own pages, and states on one of them that they are the same machine
Geothermal heat pumps	about $17,300	a published bottom end of $2,199 that the same page's own loop table rules out
A whole system	about $13,300	one publisher prices an air conditioner three different ways across two of its own pages

Floors, fans and ducts

Page	The short answer	What it adds
Radiant floor heating	about $4,000	a seven-row table both publishers print identically, which is one multiplication wearing a table's clothes
Attic fans	about $450 to $624	the mount and power source span more than the two publishers' averages do, and we say where the data is stale
Air duct cleaning	$300 to $800	the highest published figure comes from the trade association of the firms selling it

Repairs, parts and upkeep

Page	The short answer	What it adds
AC repair	about $370	two averages six dollars apart, and the rule for when repairing stops making sense
Boiler repair	about $450	the quoted $413 average is for service, which is a different job, and we separate them
Heat pump repair	$400 to $798	one publisher's average sits above the other's stated maximum, and the type you own explains it
AC compressor	about $1,200	the repair-or-replace rule of thumb worked through, and why no compressor price can pass it
Evaporator coil	about $1,350	two publishers agreeing to the dollar on three figures, and the small print where both say why
Furnace blower motor	about $515	a headline range that the same guide's own horsepower table runs straight past
AC capacitor	about $170	a $9 part inside a $170 job, and the four failures that waiting on it causes
R-22 Freon	$50 to $80 a pound	banned since 2020, three and a half times the price of modern refrigerant, and why that usually settles the repair-or-replace question
Maintenance and tune-ups	$75 to $200 a visit	four figures that look like a contradiction and turn out to be one system against two

When something goes wrong

Page	The short answer	What it adds
AC not cooling	usually cheap, sometimes not	a price against every named cause, and the refrigerant sentence one publisher prints and the trade rarely repeats
AC freezing up	filter first, then refrigerant	the cause nobody expects, a unit that was too big from the day it was fitted
Furnace blowing cold air	the fan works, the burner does not	that symptom rules out the dearest part before anyone looks, and five of the eight remaining are under $180
Furnace will not turn on	four checks that cost nothing	on the first cold day the queue is the real problem, which is why the fix is a test run in September
A loud system	usually airflow, not a fault	ten decibels is half the loudness, and the cheapest fix is a vent cover

Choosing, sizing and lifespan

Page	The short answer	What it adds
Heat pump vs furnace	the heat pump costs about 1.7 times as much	one publisher's comparison page uses 2024 borrowed data its own cost page has since overtaken, and we show the footnote
Mini split vs central air	it depends entirely on the ducts	the averages and the Department of Energy give opposite answers, and we show what each is counting
What size air conditioner	fewer BTU than the rule of thumb says	the 20 BTU rule oversizes a large house by half, measured against a published table
How long it all lasts	10 to 25 years, by machine	every lifespan in the section in one table, with who told each publisher
How a heat pump works	it moves heat, it does not make it	why its efficiency ratings cannot be compared with a furnace's, and the 120 degree ceiling nobody mentions
Furnace vs boiler	the ducts or pipes decide it	the choice is really about distribution, not the machine, and we say where the source's own pros and cons list is scrambled
What a SEER rating is	miles per gallon for an air conditioner	both rating scales printed side by side, and the 4.5% conversion checked against all eight rows of the table it comes from

If the heat is getting in or out through the glass rather than the machine, our windows section prices that side, including repairs when only one window is at fault.

Where the numbers come from

Fixr, whose heating and cooling guides were updated between August 2022 and January 2026. This Old House, whose guides were updated between March and October 2026. Bob Vila, whose guides date from 2022 to 2024. Each page names which, down to the specific guide. The two attic fan guides are the oldest pair we use anywhere, and that page says so at the top rather than in a footnote.

Three things we flag wherever we meet them. Where a source takes a figure from a company that profits from the work, we name that, as on the duct cleaning, evaporator coil and boiler repair pages. Where a cost guide sits directly above a form that sells your details to contractors, as This Old House's air conditioner, evaporator coil and boiler pages do, we say so and use the figures anyway. And where two publishers agree suspiciously closely, we check before calling it confirmation: on the evaporator coil they shared an upstream source and both disclosed it; on radiant floors the shared table turned out to be a multiplication; on boilers the convergence survived the check and we say that too.

A word on what this section does not cover yet

Three topics with real search demand are blocked for lack of a second publisher, and we will not build a page on one source: furnace repair, ductwork and whole house fans. Boiler replacement was on this list until a second dated guide appeared, which is how it came to be written. If a second usable guide appears for the others, they get written too.

One topic is blocked for a different reason. There is real demand for how often to change an air filter, and the best guide we can reach declines to give an interval at all, on the grounds that it depends on the house. We think that is the honest answer, and it is not one we can build four key figures around, so we have left it.

Not the same as a heat pump water heater

A heat pump that heats your rooms and a heat pump that heats your hot water are different machines at different prices. The hot water one lives in our water heaters section.