Restoration Guide: HVAC -- Cooling
Editor's Note: This is article 5 of 16 in Chapter 8: The HVAC/Plumbing Guide of Old House Web's Home Restoration Guide. This guide was developed and edited for old homes from original materials in the U.S. Housing and Urban Development (HUD) Rehab guide.
An old house was designed to be cooled with open windows and shade trees. The availability of electricity brought the cooling breezes of ceiling and oscillating fans. In this article, options for adding a cooling system during your older home restoration are discussed.
Section 1--Adding a Cooling System during Home Renovation
Central cooling systems did not become common in homes until the 1980s. As of 1970, only about a third of new homes were built with a designed cooling system. Old houses were often built to take advantage of shade from trees and cross breezes through open windows. Window treatments may have been used to help keep out the heat of summer afternoon sunshine. Over the years, one or more window air-conditioners may have been added to provide cooling for certain rooms, and if your old house was remodeled during the last 20 years, it may even have a central cooling system.
Today more than 75 percent of the new homes in this country have some variety of central air-conditioning, and that percentage is even higher in the south. Even if you are comfortable in your old house with the open windows and shade tree method of cooling, you may want to consider installing a central cooling system to make your home more attractive to prospective purchasers when the time comes to sell.
Section 2--Updating or Installing Cooling Systems
If your home already has window units or a central cooling system, if it is over 10 years old, the equipment is probably much less efficient than today's units. Units built after 2009 also feature more environmentally friendly refrigerant than older units.
2.1: Add Ceiling Fans During an Older Home Renovation
Ceiling fans can make a room feel more comfortable during hot weather by moving the interior air around. Ceiling fans can be operated by wall switches or remote control, and can be reversed during cool weather to redistribute heated air.
2.2: Add Power Attic or Rooftop Ventilators
The attic space of an old house can become very hot during the summer months, especially with a dark or non-reflective metal roof. A very hot attic can make it more difficult to cool the living space below. An attic fan or rooftop ventilator helps move the air through the attic, pulling cooler air in through the roof vents and exhausting it through the fan or ventilator.
2.3: Add a Whole House Fan or Ventilator
This cooling device is usually installed in a hallway ceiling below the attic space. The fan pulls warm air out of the living space and exhausts it into the attic space where it leaves the home through the roof vents. The system also pulls in cooler outside air through open windows. In moderate climates a whole house fan may be able to take the place of air conditioning.
2.4: Cover Attic Ductwork with Radiant Barriers
Radiant barriers are foil, paint, or other materials that help reflect heat. They operate best in areas of the country that get very hot during the summer. Radiant barriers are used to cover ductwork in an unconditioned attic space where they help reflect the roof's heat from the cooled air in ductwork. Depending on the size of your roof area, you may be able to reduce the size of your cooling system with radiant barriers.
2.5: Add an Evaporative Cooler While Remodeling
Evaporative coolers are designed to be used in dry climates such as the southwestern part of the country. They cool the air by evaporating water into it by either a direct or indirect method. They can provide outstanding interior ventilation, as they normally use 100 percent exterior air. If an evaporative cooler is operating correctly, it can reduce the interior temperature of a home from 95 degrees to 75 degrees, and at the same time increase the relative humidity from 15 percent to 50 percent.
2.6: Add an Electric Air Conditioner
Adding an electric air conditioner can be as simple as installing a window unit to cool a bedroom or the living room in your old house, or it can be the addition of a large central unit that works with your warm-air furnace. Central systems usually use the same ductwork distribution system as the warm-air furnace. If you are considering installing this type of cooling system in your old house, it might be advisable to use two speed indoor fans. Depending on the climate where you live, you might need a higher speed fan during the cooling season, and the lower speed should suffice for when you need heat.
Another option for electric air conditioning is the packaged terminal air conditioner, which can be installed through an exterior wall and provides both heat and air conditioning to a limited area.
2.7: Gas-Fired Chillers
If you live in a part of the country where electricity is expensive, but you want an option for cooling your old house, you might want to try a gas-fired chiller. These are gas powered exterior units which provide chilled air to an indoor air handling unit. These units have a high initial cost and can require more maintenance than electric options, but they can cost less to operate if gas is inexpensive in your area.
Jeffrey Anderson has a Degree in English from V.M.I. and served as an officer in the Marine Corps. He worked in Residential and Commercial construction management for 25 years before retiring to write full time.