Giving you the information you need to improve the safety, comfort and value of your living space. .

10 Types of Filters in your House – Where are they?

Air and Water Filters in your house benefit at least two aspects of your life; Health and Cleanliness.     Every house is different, so it’s important that you find out what you’ve got.   Filters can range from a complicated assembly to a simple screen.   When changing a filter, record the date it was changed, and where possible write the date on the filter itself.

Where are they and what do they do?

  • Furnace
  • Dryer
  • Humidifier
  • Electronic air filter
  • HRV
  • Windows
  • A/C housing
  • Condensate
  • Water filters
  • Range Hood


Furnace filter

Furnace filter

That’s what comes to mind for most people when you mention a filter in a house.  One of the first things you should do when taking possession of a house is to change the furnace filter.   Think about it – it’s got other people’s dust and dander on it.   Start fresh.   Write down  the size and note which way it’s installed.  With some filters it matters which direction the air is flowing, so don’t get it backwards.  Check your furnace manual to be sure what you should have.    Most large hardware/home stores carry the standard sizes.   Replace it at the start of each heating season, at least.   If you have central air conditioning, this filter will be catching stuff year round. Check it monthly and change it if it looks dirty.


Dryer lint trap

Dryer lint trap

Always clean the dryer filter after every load.    This will help reduce the amount of lint going down the whole dryer duct inside your house.     Having excess lint in your dryer trap can cause the dryer to work harder and even overheat.   Go outside and feel the airflow coming out of the exhaust vent when the dryer is running.   There should be a strong, hot flow of air once the dryer has been running a few minutes.  Have the dryer ducting between the dryer and the exterior cleaned about once a year.   If this duct becomes clogged, there are the possibilities of overheating and fire.    Here’s a helpful link for more information

Electronic Air filter


Electronic Air Filter

Some furnaces come equipped with this filter, and there are various configurations.   Find the manual and become familiar with it’s operation. You can pull out the filters and check them, make sure they are clean and in place.   Hire a forced air heating specialist if you are unsure about how to operate / clean it and have them show you how it works.





This is not formally a filter, but its operation will affect your air quality, and it may have a screen or a sponge that can get clogged.   Check the manual to see how it operates.    Many older furnace mounted humidifiers have been neglected or abandoned.   See if yours works; call a heating specialist to service it if you are not sure.   Winters in Toronto can be pretty dry and it is best if you can keep the humidity level in your home between 35 – 50%.

Heat Recovery Ventilator (HRV)



Many new energy efficient homes come with HRV’s.   These provide a source of fresh filtered air into the house and exhaust the stale air.   Most route the air in and out of the furnace ducting.    HRV’s have several filters including sponge sheets as well as the corrugated core.    Vacuuming or washing with soap and water usually does the trick – follow the instructions in the owner’s manual.  Sometimes instructions are labelled inside the unit too. These filters are very important for air quality in today’s newer, tighter houses.



Window screens

Window Screen

Window Screen


Believe it or not, these are filters – bug filters!   But they get dirty too, and sometimes torn.    Check your window screens in the spring for tears or looseness.    Wipe very gently with a  damp sponge.




Air Conditioner or Heat Pump


Air Conditioner

Check the outside of the  housing for buildup of debris, which can impact the efficiency of the unit.    Grass clippings and dryer lint particularly can foul the grates.  Be careful not to dent the heat exchanger fins, if exposed (more common on older units).   These look alot like a car radiator, or the outside of a window A/C unit.   Keep the area around the unit free of plants and materials, to help the air to flow freely for best efficiency.




Kitchen Range Hood

Filter on range hood - testing flow with tissue

Filter on range hood – testing flow with tissue

Check the screens under the fans – they will accumulate grease and dust over time, reducing their effectiveness.  Clean the screen according to manufacturer’s recommendations.  If the unit recirculates air through the hood back into the room, it will likely also have a carbon filter behind the screen.  Replace these as needed.




Water filters

Undersink water filter

Undersink water filter

Is your drinking water filtered under the sink?   Do you have a water softener?   Make sure these are maintained per manufacturers instructions.   A clogged water filter can be worse than none.





Condensate neutralizer

Condensate filter

Condensate filter

Gas furnaces may  have a condensate filter on the condensate drain line to keep the acidic water discharge from polluting the city waste water.      Check your furnace manual and look around the outside of the furnace to trace  the drain line.



Now take a few minutes to walk around your house and look for these items.  My home inspection service will guide you through the specifics of your house and I will even find operating manufacturers manuals for you if you need them.    This is what I do to help owners improve the comfort, safety and value of their homes.

Plumbing Emergencies


  • 1. Where is the main water shutoff valve inside the house?
old water shut off

Old style water shut off

New Water Shut off

New style quarter turn valve

If there is a leak in a water supply pipe, you will want to turn off this valve FAST to prevent flooding in the house. Usually you can find this valve upstream of the water meter, in the basement at the front of the house. If this valve is really old or seized, it may not work, or worse, break or leak itself. Get a plumber to remove the old one and install a new one.

City Water Valve

City Water Valve in sidewalk

Sometimes the pipe can fail or be broken upstream of the main inside shut off valve, in which case the city supply has to be turned off.  Usually this valve is outside of the house in your lawn or sidewalk. Typically only the city can operate this valve.

      • 3. Where are the shutoffs for water fixtures?

If a fixture such as a toilet or faucet leaks, you can shut off the water supply to just the one fixture, if valves are installed for it. Sometimes they are not, which is a pain because then you have to shut off the water for the whole house to fix the problem.

Toilet water shut off

Toilet water shut off

        • 4. Who do I call if a pipe breaks inside the house?

Make sure you have the number handy of a plumber who does 24-7 emergency calls. Good idea to put it on your fridge, and on your phone.

      • 5. Who do I call to shut off the city water?

In Toronto, Dial 311 if you can’t shut the water off in your house from the inside. Tell them you have a plumbing supply leak emergency and you need the City to come and shut off the valve right away. Ask them how long it will take, and make sure you call a plumber too.

      • 6. Where is the basement drain?
Basement Drain

Basement Drain

Find the drain in your basement. It’s possible it has been covered with flooring. Keep it uncovered. If you have a water leak while you are away, the water needs to drain out.


A Meticulous Home Inspection includes a guided tour to show you the important features, like water shutoff valves, and drains in your home.