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When a House Feels Too Cold
Contributing Solutions | Building Envelope and Duct Solutions | Air Sealing | Insulation | High Performance Windows | Duct Sealing | Heating and Cooling Solutions | High Efficiency Gas Furnace | Hydronic Forced Air Heat | Radiant Hydronic HeatOverview
It is common for a home to feel uncomfortably cold and drafty, especially in the winter.
The walls, floors, roof, and windows form an envelope which should protect the house from the chilly outdoors and keep heat in. Most houses are poorly insulated and let heat out and cold air in. This cold air is actually sucked into the house by the stack effect and makes the heating system work harder to heat the home. The problem is made worse when the furnace, ducts, or radiators can’t get heat to the house efficiently, due to improper sizing, design or installation.
This common problem can be solved by considering the home as a system.
Contributing Solutions
To solve the problem of an uncomfortably cold house all contributing root causes must be addressed. The house is a system and as with many systems the whole is greater than the sum of the parts. For example, installing an efficient furnace and good insulation will do more to help 
keep a house warm when they are installed together than if they are installed separately. Here are the main things to be considered in a house which feels too cold:
- Reduce the amount of heating a house needs with air sealing and insulation
- Help the duct system deliver the appropriate amounts of warm air to the house
- Make sure the heating system is working properly and well adjusted, since less heating will be needed in a well insulated home
Building Envelope and Duct Solutions
These solutions should be addressed first to improve a home’s ability to retain warm air and to assure that the ducts are delivering warm air to the rooms which need it instead of wasting it in the attic or crawlspace. The building envelope and duct system need to work together with the heating and cooling system to make sure that the home stays comfortably warm.
- Air Sealing: A tight building envelope makes insulation more effective and helps stop entry of cool air from below the house which replaces warmer air that is lost through the attic via the “stack effect”.
- Insulation: Added insulation will be much more effective in an air sealed home. Insulation will help stop heat loss from the building when installed correctly.
- High Performance Windows: Well engineered and well installed windows can add additional insulation and air sealing, while reflecting radiant heat back to the occupant
- Duct Sealing: Properly sealed ducts will deliver more heat or cool to where it’s needed instead of letting it leak into the attic or crawlspace, making a big difference for large rooms or for rooms furthest from the furnace or air handler. This effect will be compounded in a home which can maintain constant temperatures thanks to air sealing and insulation.
Air Sealing
Air infiltration in typical houses is roughly split:
- 1/3 floors, walls, and ceilings
- 1/3 ducts, vents, plumbing penetrations, and electrical outlets
- 1/6 windows and doors
- 1/6 fireplace
Gaps, cracks, and small holes in all of these areas must first be sealed for insulation and heating and cooling systems to be effective. Air sealing addresses uneven heat between different rooms in a house by eliminating drafts and temperature differences in the home which result from the stack effect, where cold air enters the home from beneath and hot air exits from above.
Air sealing from above reduces the force of the stack effect and sealing from below raises the pressure plane (under which air gets pulled into the house), improving indoor air quality and saving energy during the cooling season.[+] MORE
Insulation
In general, more heat is lost through walls, floors, and ceilings (which are generally poorly insulated) than through windows; since insulating these areas is generally more cost-effective than replacing old windows in an existing home, proper insulation and air sealing should come first. Properly installed insulation addresses uneven temperatures by minimizing temperature variability indoors and helps keep rooms warmer in the winter, particularly in rooms exposed to cold (such as a basement or a room over an uninsulated garage or crawlspace). [+] MORE
High Performance Windows
High performance windows save money by insulating the home from conductive or radiant heat loss or gain, as well as by protecting furniture and fabrics from fading. A poorly insulated window actually draws heat out of the room when it is very cold outside. This makes sitting near such a window uncomfortable because it feels drafty in the winter. Once a home has been well sealed and insulated, high performance windows can address a drafty or cold house by stopping heat from flowing through a large window. High performance windows such as Serious Windows also provide a tight air seal to reduce air leakage in the building.
Depending on your climate, a more cost effective alternative to window replacement can be installation of a reflective window film such as 3M Prestige or Night Vision window film [+] MORE
Duct Sealing
Most duct systems have a more or less widespread problem of air leaks, from many small holes to several-inch-wide gaps between duct joints. Duct sealing, which is among the most cost effective of home performance retrofits, prevents conditioned air from leaking out of ducts and crawlspace or attic dust from infiltrating the home. Well sealed ducts will be better able supply sufficient heated air to all parts of the house. [+] MORE
Heating and Cooling Solutions
It is common to only think of a furnace when considering improving a home’s heating system. However, heating and cooling systems work together with the building envelope and duct system to deliver and retain warmth and cool to the home. For example, good insulation can be considered part of the heating system since heat that it retains is heat that the furnace does not need to generate. High efficiency heating and cooling systems such as energy star furnaces and air conditioners can cost less to run, but they will be most effective at delivering comfortable temperatures throughout the house when operating in conjunction with a well sealed and insulated building envelope and with an effective duct system which doesn’t waste the energy used to cool or warm the air.
- High Efficiency Gas Furnace: A smaller, more efficient furnace installed with a well sealed and insulated building envelope and duct system will efficiently deliver heat to the home, especially if is well calibrated.
- Hydronic Forced Air Heat: This alternative to a furnace can deliver more even temperatures in rooms and throughout the house by operating on longer cycles at lower temperatures (than furnaces), thereby avoiding temperature drops between cycles which make the house feel cold.
- Radiant Hydronic Heat: Radiant heat feels more comfortable and long lasting than poorly adjusted forced air heat because it warms people and furniture instead of the air.
High Efficiency Gas Furnace
The highest efficiency energy star furnaces are 10% to 20% more efficient than other furnaces. An inefficient furnace, or one that is undersized may take a long time to heat up and may not be able to deliver enough heat to the further corners of the home. A furnace which is oversized (a common occurrence) may heat up so quickly that it doesn’t run long enough deliver warm air and mix it with the air in the house. A correctly sized and calibrated system will deliver the right amount of heat to the right places in the home, helping to deliver the right amount of heat to each room.
It is especially important to first improve the building envelope and duct system because doing so will generally mean a smaller furnace (which burns less fuel than an equally efficient furnace of a larger size) will be appropriate to heat the house. [+] MORE
Hydronic Forced Air Heat
Hydronic forced air uses heated water to deliver heat to the air duct system as an alternative to a furnace. A correctly sized and calibrated hydronic forced air system delivers more constant even temperatures than a traditional furnace. This can help avoid the temperature drops which come from a furnace quickly heating a house and then turning off, making the house cool off and feel drafty. [+] MORE