How to Improve Air Quality In an Old House


The approach to indoor air quality (IAQ) is not the same in old homes. The age of a home is a major factor, and older homes are often plagued by stale, stuffy air.

But how do you improve air quality in an old house? First, the home must be brought up to safety by removing dangerous pollutants and old building materials. Second, it should be better insulated to become more energy-efficient and retrofitted with a modern central air system.


Pollutants In Older Homes

Although both new and old homes are subject to indoor pollutants, there are some pollutants that can particularly plague older homes.



Lead Paint

Homes built prior to 1978 were painted with lead-based paint. While the sale of lead paint has been banned, many homes in the United States have lead paint walls that have probably since been painted over with latex paint.

The EPA states that only 24% of homes built from 1960 to 1977 have lead paint, while 87% of homes built prior to 1940 have lead paint. Although the EPA isn’t specific, we’re told that the number of US homes that have lead paint are in the millions.

Lead poisoning occurs from loose chips falling off and the dust in the lead, so great care must be taken not to agitate the lead and create even more loose matter. If you’re in this situation, you’ll have to regularly wipe surfaces with a moist cloth and vacuum and mop regularly to not allow any dust build-up. Damp also contributes to this problem, so buying a dehumidifier (especially in the summer) is probably a good idea.

Children and elderly occupants should also regularly undergo a blood test every few years to be checked for lead levels just to be sure they’re safe.


Lead Plumbing Pipes and Fixtures

Some homes also had lead plumbing pipes at some point decades ago, although this surprising could happen in newer homes.

In fact, it’s said that even newer homes can have up to 8% lead in piping, solder, and fixtures, despite the pipes being marketed as “lead free”. The 2014 Safe Water Drinking Act was signed to lower the lead limit to 0.25% and expanded the regulation to include plumbing fixtures as well.

If your home has lead pipes, it could be quite costly to replace them (up to $10,000 for the average home). Many cities, however, have lead abatement programs and offer financial assistance to encourage hesitant homeowners to replace the pipes on their property.

One piece of good news is that the situation can be somewhat alleviated by attaching a specialty filter to the tap and cleaning out the aerator on each faucet. In fact, the Aquagear water filter was tested in Flint (MI) for lead removal and claims to be able to remove 99.9% of the lead in the water.



We’ve all seen the mesothelioma commercials, warning that asbestos is dangerous.

Sadly, asbestos was prevalent in older homes, thanks to its cost and fire resistance. To our younger generation, it seems as if anything with a surface had asbestos on it – flooring, wall insulation, siding, sheetrock, roof, pipes, ducts. Most people think of insulation when it comes to asbestos, but the truth is that asbestos was in nearly everything one way or another.

Finally when it was found to be a carcinogen, it was banned in 1978 along with lead paint.

If you have an older home, removing asbestos may be a difficult task. While removing asbestos insulation is doable by a professional remediation team, how do you remove asbestos that has been mixed in with cement?

Similar to their advice on lead paint, the EPA also advises that a home with asbestos is generally safe, as long as the asbestos isn’t chipping off or falling off in the form of dust.



Any home that’s many decades old will inevitably have a moisture issue, especially if it has a basement. And when moisture is combined with optimal temperatures and organic building surfaces, mold thrives.

If the mold issue is minor, you may be able to clean and remove it yourself, and then maintain low humidity levels with a dehumidifier by keeping relative humidity levels below 50%.

However, professional mold remediation will also be necessary for severe cases.

Another cause of mold is the lack of exhaust fans in kitchens and bathrooms. Unfortunately, older homes typically didn’t have those, so you will have to purchase and install exhaust fans throughout your home. It’s an absolute must nowadays.



Radon isn’t necessarily an old house versus new house problem. All homes are equally prone to radon exposure. In fact, 1 in every 15 United States homes has elevated radon levels.

Radon levels are mostly a factor of the soil that a home is built on. It isn’t unusual for one home to have high radon levels, while another home that’s just a few blocks away is perfectly fine. This also has to do with how the house was built and how permeable it is to soil gases like radon.

If a radon level reveals that a home has high radon levels, a remediation system must be installed to allow the radon to vent away from the home through the attic. This can be expensive, but radon mitigation fans are available on the market as well in milder radon cases.  More on radon in this post.


Phthalates and Formaldehyde

While very old homes enjoyed natural flooring materials like linoleum and hardwood, homes that are built after the 1950s have increasingly been built with less natural and less safe flooring materials.

By the 1960s, mostly all linoleum was replaced by polyvinyl chloride (PVC) flooring materials. It wasn’t until recently that PVC flooring was found to have high levels of phthalates, chemicals that disrupt hormonal development in male children. The PVC itself has been classified as a carcinogen. You can read more about what’s in vinyl flooring in this post.

Laminate flooring became prevalent in the 1980s, but it too has recently been found to contain undesirable chemicals. Namely, a volatile organic compound (VOC) known as formaldehyde, which also is a carcinogen.

There are some good news, however.

1 – Major home improvement stores and flooring manufacturers have moved to eliminate or reduce these chemicals in their vinyl and laminate flooring since 2015.

And 2 – If you’ve purchased an older home that happens to have vinyl or laminate flooring, chances are that most of the VOCs have already off-gassed from the surface and aren’t as dangerous as they were when the products were new.


Older Homes Are Less Insulated

Older homes were built to be less airtight and are more drafty. Their windows, doors, baseboards, and other building materials were built to “breathe”. It’s great if you want to allow fresh air in, but not so great if you’re looking to be energy-efficient and save on your utility bills.

But before you consider retrofitting your old home with fancy new systems, you’ll first have to take a look at its current state.

Blowing insulation into the exterior walls of an old home is inadvisable, especially if you haven’t figured out where the excess water will run off and how the walls will be able to dry. The fact is that cellulose insulation retains water, so the last thing you should want is for water to linger inside the walls after a rainy day.

Most homeowners are tempted to do the bare minimum as a quick solution to keep utility costs down, but doing the bare minimum will also destroy the home over the long run.

Instead, you’ll have to remove the weather barriers and reinstall them, do the flashing again and install new well-insulated windows. And even then, you’ll probably have to do some more since the house will continue to leak air.

If you really want to get the most out of your budget and resources, focus on insulating the foundation walls, windows, doors, and the attic.


Installing Central Air Systems

Many old homes were built before central air became widespread, so you’ll probably have to start thinking about installing a central air system.

A home should exchange about a third of its indoor air per hour, according to the ASHRAE 62 building standard. If your old home is drafty, it probably exchanges air more quickly. Great if you want fresh air in your home, but not so great when the utility bill arrives at the end of the month.

Speaking of bills, it will cost roughly $4,000 to $8,000 to add central air system to an existing forced-air heating system in an older home with about 2,000 sq. ft. of space, depending to how much ducting will need to be reconfigured or added. Although, if the ductwork and clunky air handler necessary may seem a bit too much for your home, you can always consider a ductless split system as an alternative to a central system. Mini ducts are also another alternative.

The technician will also perform a load calculation to determine what size of the AC unit you need. If you did a good job insulating the home, you may find that your home may not need as large a unit as it otherwise would.

But still, make sure you’re not undercutting yourself and are indeed getting the right tonnage, (BTU/hour). AC units that are too small might be cheaper immediately, but will end up costing more to operate, and will also leave your home damp. This may also require upgrading your electrical system to be able to handle the new AC unit.

If you really want a unit that’s good on the budget, ask your AC technician about something called the seasonal energy-efficiency rating (SEER) instead. The SEER is a measurement of how much heat an AC unit can remove per each watt that’s consumed.


Old Furnaces and Appliances

Most furnaces have a 20-year lifespan anyway, so it’s possible to have an older home with a newer furnace that’s well maintained.

Old, faulty furnaces can give off carbon monoxide, so it’s imperative to make sure they’re in good working condition and properly venting to the outside. Carbon monoxide is created through a process of incomplete combustion, and because it’s odorless and difficult to detect, carbon monoxide monitors are essential in every home.

Newer building codes now also require several carbon monoxide monitors to be installed, so you’ll need to equip your old home with a monitor on each floor and near the bedroom and garage areas at minimum. Also, carbon monoxide monitors do have a life span (about 7 years), so just because the old home you recently purchased has carbon monoxide monitors, it doesn’t necessarily mean that they’re working properly.

Your laundry dryer, water heater, and fireplace are other areas of your home where incomplete combustion can occur as well, so you’ll have to make sure they’re also properly venting to the outside.



Old homes may come with a certain type of charm that’s unmatched by new construction homes, but they also come with building materials and building methods that are a greater health hazard to its occupants.

When buying an old home, you’ll have to check it for asbestos, lead, and other pollutants that can plague most homes out there. You’ll also find that the home needs to be better insulated and may need to be fitted for a new central HVAC system.