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Heating & Cooling How To & DIY

Improve the value of your home by discovering our heating & cooling step-by-step tips & ideas.

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How To Install Central Air Conditioning

Want to install central AC in your home? Read this guide to learn more about central air, from installation costs to selecting the best unit.
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How to Retrofit Radiant Heating in a Bathroom

In this video, This Old House plumbing and heating expert Richard Trethewey helps a homeowner install a radiant floor system in their bathroom.
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How to Upgrade to a Heat Pump System

Energy-saving, climate-friendly, and relatively easy to retrofit, air-source heat pumps are now a viable option for heating and cooling, even in cold climates. Here’s how to put them to work in your home
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How to Create a House HVAC Plan

Richard Trethewey demonstrates heat loss and gain to design a balanced HVAC system.
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Why is My Furnace Blowing Cold Air?

Most people will agree that central heat is one of the more essential modern conveniences—so when it stops working, your home can get uncomfortable fast. If you have a forced hot air system that has suddenly started blowing cold air, there are a few things that you can try to get the heat going before you call the furnace repair person.
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How to Weatherstrip a Wood Door

Enhancing the energy efficiency of an old, drafty door with This Old House general contractor Tom Silva
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HVAC Air Balancing: What You Should Know

If you’re struggling with maintaining—or even attaining—a consistent temperature throughout your house, your HVAC system may be out of balance. This guide will explain the basics of air balancing, including how DIYers can tackle the job and when they should call a professional to sort out their home’s heating and air conditioning system.
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All About Radiant Floor Heating

Whether it’s warming a large addition or a cozy bathroom, radiant heat underfoot invisibly ups the comfort level. Here’s the lowdown on some of today’s most popular systems.
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How to Replace a Tank-Type Water Heater

In this DIY Smarts segment, plumbing and heating expert Richard Trethewey helps a homeowner be proactive about their home maintenance by replacing their existing tank-type water heater before it fails.
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How to Get Your Furnace Ready for Winter

Your furnace may need some TLC before starting it up this winter. Here are some tips on what to do to get your furnace prepped before the cold months arrive.
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All About Smart Thermostats

Home technology expert Ross Trethewey explains everything there is to know about modern smart thermostats.
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How to Install a Window AC Unit

Window air conditioning units are quite easy to install. With a bit of background knowledge, the right tools, and a guide to show the way, cooler temperatures are on the horizon—even when it’s boiling outside.
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How to Bleed a Radiator

If you have hot-water heat, have you ever found that one or more of your radiators isn’t warming up? Or that only the bottom of a radiator gets hot? Before you spend the money on a plumber, try an easy fix.
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What to Do If Your Fridge Stops Cooling

Is your refrigerator no longer staying cool? There are a number of reasons why your fridge may be quitting on you. Read our guide to help diagnose and fix your fridge.
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How to Build an Outdoor Air Conditioner Cover

Air conditioning is nice to have, but the look of the clunky unit outdoors can be unsightly. Watch as Jenn Largesse, DIY Expert and House One Editor, creates a wooden cover for her air conditioning unit.
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How to Upgrade to a Smart Thermostat with Four Wires | This Old House: Live

Ask This Old House home technology expert Ross Trethewey demonstrates how to install a new smart thermostat without an existing common wire. This video is part of This Old House: Live—an initiative providing daily programming and opportunities to connect with our experts during these challenging times.
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How to Upgrade to a Smart Thermostat without Changing the Wiring

Ask This Old House plumbing and heating expert Richard Trethewey replaces an old thermostat with a smart thermostat without replacing the original two wires in the wall.
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How to Seal Leaky Ductwork

Improve the air quality and keep your home energy efficient by sealing your ducts.
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How Do Smart Thermostats Work?

Learn about features, installation, and the difference between traditional and smart thermostats.
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How to Diagnose and Repair a Humid Air Conditioner

Ask This Old House plumbing and heating expert Richard Trethewey travels to Orlando to diagnose and repair an HVAC system that is creating way too much humidity
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How to Heat a Garage Workshop

Ask This Old House plumbing and heating expert Richard Trethewey travels to Akron, Ohio to install a garage heater.
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How to Install a Whole-House Ductless System

Ask This Old House plumbing and heating expert Richard Trethewey shows a style of ductless heat pump that can be used to heat and cool an entire house
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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
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How an Energy Recovery Ventilator (ERV) Works

Richard Trethewey explains how an Energy Recovery Ventilator (ERV) replaces conditioned indoor air with fresh outdoor air without wasting energy
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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
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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.
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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.
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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.
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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.
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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
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Before You Store That Air Conditioner

Carrying it to the basement isn’t just challenging, it’s dangerous, partly because it can block your view of the steps. Here, ways to save your back—and maybe a trip to the ER
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How Thermostat Setbacks Save Money

This Old House plumbing and heating expert Richard Trethewey explains how adjusting the thermostat can reduce energy consumption and save you money.
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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