Heating & Cooling
How to Choose and Use an Air Conditioner for Your Home
Ask This Old House plumbing and heating expert Richard Trethewey walks host Kevin O’Connor through the choices in air conditioners.
How To Install a Whole-House Ductless System for Your Home
Looking for a more energy-efficient way to heat and cool your home? Learn all about whole-house ductless systems in our comprehensive guide.
Take the edge off your energy bills – meet the heat pump water heater
Your home’s most forgettable appliance could be wasting hundreds of dollars per year
How to Maintain an Air Conditioner
Ask This Old House plumbing and heating expert Richard Trethewey shares tips for keeping an air conditioner running efficiently
How an Energy Recovery Ventilator (ERV) Works
Learn how an energy recovery ventilator (ERV) works and the benefits it provides in this guide and video featuring Richard Trethewey.
The Pros and Cons of a Steam Heating System
Considering steam heat? We help you weigh the pros and cons so you can decide if it is right for you.
Sizing up a Home Heating System
Richard Trethewey explains how to assess a home’s heating system – and figure out whether you’ll need to replace it
How to Replace a Steam Radiator
Ask This Old House plumbing and heating expert Richard Trethewey replaces a small radiator with one that’s the correct size
How To Improve Attic Ventilation
Learn how to identify when your attic doesn't have proper airflow and how to improve attic ventilation in our guide.
Read This Before You Buy Ductless AC
These quick-to-retrofit ductless AC systems provide unrivaled operating efficiency and room-by-room zoning comfort.
Installing Central Air Conditioning: A Comprehensive Guide
Tired of your window AC unit? From split units to zoned systems to ducts, here’s what you need to know about how central AC systems work.
10 Handy Air Conditioning Tips to Keep Your Home Cool
Beat the heat by having the cleanest, coolest, and most efficient air conditioner on the block with our top 10 tips.
How to Install a Wall Mounted Space Heater
Ask This Old House master electrician Scott Caron warms up a chilly bathroom by installing an electric convection heater.
How To Diagnose Problems With a Hot Water Heating System
Ask This Old House plumbing and heating expert Richard Trethewey helps a homeowner figure out why one of her radiators is not working.
How to Remove an Old Fuel Tank
Before the heating system at the Arlington project house could be upgraded to natural gas, the old oil tank had to be taken away.
How to Install Room-By-Room Zoning in an HVAC System
Ask This Old House plumbing expert Richard Trethewey learns about an HVAC system that allows each room to be zoned out using smartphone technology.
All About Ceiling Fans
These air movers keep you cool and look cool doing it. Here’s how to choose a model that’s right for your space
Ask This Old House: Richard Trethewey’s Greatest Hits
Over the years, This Old House plumbing and heating expert Richard Trethewey has helped hundreds of homeowners reduce their energy consumption and slash their monthly utility bills
How Thermostat Setbacks Can Save You Money
Learn from plumbing and heating expert Richard Trethewey how using thermostat setbacks can help you save money.
How to Seal Leaky Ductwork
Ask This Old House plumbing and heating expert Richard Trethewey shows an innovative new way to seal ducts from the inside
How to Install an Exhaust Fan in a Wall
Scott Caron, master electrician for Ask This Old House, helps a homeowner put in an exhaust fan to rid her kitchen of smelly cooking odors.
How To Install a Whole-House Dehumidifier
Too much humidity in your home can cause discomfort. Learn how to install a whole-house dehumidifier in our comprehensive guide.
How to Install DIY Radiant Floor Heating
Use a specialized foam panel to lock the PEX tubing in place, cover it with a sand-and-cement mix, and tile away.
How To Zone a Forced Air Furnace and Air Conditioner
Control temperatures in different rooms according to comfort level by following our guide and instructional video to zoning your HVAC system.
How to Install a Whole House Humidifier
Ask This Old House plumbing and heating expert Richard Trethewey shows how a professional would install a whole-house humidifier.
How to Repair a Frozen Air Conditioner
This Old House plumbing and heating expert Richard Trethewey shows how to prevent ice buildup from shutting down an air-conditioning system.
9 Items in Your Home That Can Be Ruined by Low Humidity
Learn which household items are vulnerable in low humidity and how to remedy it.
How To Install a Smart Thermostat
In this guide, This Old House heating expert Richard Trethewey shows how to install and operate an energy-saving smart thermostat.
How to Insulate HVAC Ductwork
Watch as This Old House plumbing and heating expert Richard Trethewey helps a homeowner insulate his exposed HVAC ductwork.
How To Install a Ductless Heat Pump
This Old House's Richard Trethewey and Kevin O'Connor install a ductless heat pump to heat and cool a 700-square-foot room.
How To Diagnose Leaks in a Steam Boiler
Ask This Old House plumbing and heating expert Richard Trethewey helps locate the leak on a steam boiler that's losing water.
How a German Home Maximizes Energy Efficiency
Ask This Old House plumbing and heating expert Richard Trethewey explains how the country's building practices and lifestyle affect energy consumption