Upgrade Your Furnace Filter: Cleaner Air & Better Efficiency in London, ON

MERV 8-11 is ideal for most homes in London, ON, balancing air quality and airflow. Higher ratings (MERV 12-13) are better for allergies and capturing smaller particles like bacteria and smoke, but may require professional installation to ensure compatibility with your furnace. Higher MERV filters can restrict airflow if your system isn't designed for them. We can help you choose the right filter for your specific furnace and needs. Call us for a free assessment.

Replace your furnace filter every 30-60 days during winter heating season. Homes with pets, smokers, or allergy sufferers may need monthly changes. Standard 1-inch filters need more frequent changes than thicker pleated filters. Write the installation date on the filter to track age. A dirty filter is the #1 cause of furnace problems, high energy bills, and poor indoor air quality. Check your filter monthly during peak season and replace when it looks dirty.

Yes, if not compatible. High-MERV filters (MERV 13+) are denser and can restrict airflow, causing your furnace blower to work harder, leading to overheating, short cycling, or premature motor failure. Most standard furnaces are designed for MERV 8-11 filters. If you want higher filtration, we can assess your system and recommend the maximum MERV rating your furnace can handle. Some newer furnaces are designed for high-MERV filters. Never guess—have a professional check first.

High-MERV filters trap dust, pollen, pet dander, mold spores, bacteria, and other airborne pathogens before they circulate through your home. This creates a healthier living environment, especially important during winter when windows stay sealed. For allergy sufferers, upgrading to MERV 11-13 can significantly reduce symptoms. Clean filters also improve furnace efficiency, saving energy and extending system life. The result is cleaner air and lower energy bills.

Pleated filters have folded material that creates more surface area, capturing more particles (MERV 5-13) while maintaining good airflow. They trap dust, pollen, pet dander, and mold. Fiberglass filters are flat, cheap (MERV 1-4), and only capture large particles, allowing most allergens to pass through. We recommend pleated filters for better indoor air quality and furnace protection. The small extra cost pays off through improved air quality and system efficiency. Most homeowners notice the difference immediately.

The filter size is printed on the frame of your current filter (e.g., 16x25x1). Measure if the label is worn: length, width, and thickness (depth). Common sizes include 16x20x1, 16x25x1, 20x20x1, and 20x25x1. Never install a filter that doesn't fit perfectly—gaps allow unfiltered air to bypass the filter. Take a photo of your current filter or bring it to a hardware store to match. We can also supply the correct filters for your system and set up automatic delivery.

A clean filter of any MERV rating improves efficiency because it allows proper airflow. However, a higher MERV filter that's too restrictive for your system can increase energy consumption because the blower works harder. The key is using the highest MERV rating your furnace can handle while maintaining good airflow. For most systems, MERV 8-11 provides optimal balance. A dirty filter of any MERV rating will increase energy bills significantly. Regular replacement is more important than the MERV rating.

Signs your filter needs changing: visible gray or black buildup on the filter surface, higher than normal energy bills, reduced airflow from vents, unusual furnace noises (straining), more dust accumulating in your home, allergy symptoms worsening indoors, or the furnace short-cycling. Check your filter monthly during winter. A clean filter should appear white or light gray—if it's dark gray or black, replace it immediately. Don't wait for scheduled intervals if your filter looks dirty.

Only if it's specifically labeled as washable or permanent. Most standard pleated and fiberglass filters are disposable—washing them damages the material and reduces effectiveness. Washable filters are typically made of foam or metal mesh and have lower MERV ratings (1-4). If you use disposable filters, simply replace them. Trying to wash a non-washable filter can cause mold growth and furnace damage. We recommend disposable pleated filters for best results. They're affordable and effective.

Yes. High-MERV filters (MERV 11-13) capture common allergens including pollen, pet dander, dust mites, and mold spores. Many allergy sufferers notice significant symptom improvement after upgrading from standard MERV 1-4 filters. For severe allergies, consider MERV 13 plus a whole-home air purifier or UV light system. Regular filter changes (every 30-60 days) are essential—a dirty filter, even a high-MERV one, won't help allergies. The combination of the right filter and regular changes makes a huge difference.