Frequently Asked Questions — HVAC

Below you will find answers to the most common questions we receive from homeowners and business owners about heating, cooling, and HVAC systems. If you have a question that is not answered here, please call us at (608) 556-0324 or contact us online.

A: Standard 1-inch fiberglass or pleated filters should be replaced every 30 to 90 days. Homes with pets, allergy sufferers, or high dust levels should replace filters monthly. Check your filter monthly and replace it when it appears visibly dirty. Thicker media filters (4-5 inch) typically last 6-12 months.

A: We recommend a minimum of 16 SEER for Wisconsin homes. Higher SEER ratings (18-21+) provide greater energy savings, especially in homes with high cooling loads. The current federal minimum is 14 SEER. While higher-efficiency units cost more upfront, the energy savings typically offset the additional cost over the life of the equipment.

A: A well-maintained gas furnace typically lasts 15 to 20 years. Annual tune-ups, timely repairs, and regular filter changes can extend the life of your equipment. If your furnace is over 15 years old and requiring frequent repairs, it is usually more cost-effective to replace it with a modern high-efficiency unit.

A: A central air conditioner typically lasts 12 to 15 years with proper maintenance. Heat pumps have a similar lifespan. Ductless mini-split systems can last 15-20 years. Annual maintenance, keeping the outdoor unit clean, and timely repairs all contribute to longer equipment life.

A: Short cycling is most commonly caused by a dirty air filter restricting airflow, causing the furnace to overheat and shut off on the high-limit switch. Other causes include an oversized furnace, a faulty thermostat, a blocked flue, or a cracked heat exchanger. Replace your filter first; if the problem continues, call for service.

A: Common causes include a dirty air filter, low refrigerant charge due to a leak, a frozen evaporator coil, a failed compressor, or a thermostat set to "fan only" instead of "cool." Check your thermostat settings and replace your filter first. If the problem persists, call for service — refrigerant issues require a certified technician.

A: A heat pump is a heating and cooling system that moves heat rather than generating it. In summer, it works like an air conditioner, moving heat from inside your home to outside. In winter, it reverses the process, extracting heat from outdoor air (even cold air) and moving it inside. Heat pumps are very efficient because moving heat requires less energy than generating it.

A: A useful guideline is the "5,000 rule": multiply the age of your system by the repair cost. If the result exceeds $5,000, replacement is usually the better investment. Also consider: if the system is over 15 years old, if it uses R-22 refrigerant (phased out), if it requires frequent repairs, or if your energy bills have been increasing significantly.

A: Furnace installation costs vary based on equipment efficiency, brand, and installation complexity. Standard efficiency (80% AFUE) furnaces typically range from $2,500 to $4,500 installed. High-efficiency (95-98% AFUE) furnaces range from $3,500 to $6,000 installed. We provide free in-home estimates with no obligation.

A: Central AC installation costs depend on system size, efficiency rating, and whether ductwork modifications are needed. A typical residential installation ranges from $3,000 to $7,000. Higher-efficiency systems cost more upfront but save money on operating costs over time. We provide free estimates.

A: AFUE (Annual Fuel Utilization Efficiency) measures how efficiently a furnace converts fuel to heat. An 80% AFUE furnace converts 80% of fuel to heat; 20% is lost through the flue. A 96% AFUE furnace loses only 4%. Upgrading from an old 60% AFUE furnace to a 96% AFUE unit can reduce your heating fuel costs by 40% or more.

A: Key steps include: upgrading to a high-efficiency HVAC system, installing a programmable or smart thermostat, sealing ductwork leaks, adding insulation to your attic and walls, sealing air leaks around windows and doors, replacing your air filter regularly, and scheduling annual HVAC maintenance. We can provide an energy assessment to identify the most cost-effective improvements for your home.

A: Our furnace tune-up includes: heat exchanger inspection, burner cleaning and adjustment, igniter and flame sensor testing, gas pressure check, flue inspection, blower cleaning and lubrication, electrical connection tightening, thermostat testing, filter replacement, and a written service report. Our AC tune-up includes: coil cleaning, refrigerant check, capacitor testing, electrical inspection, condensate drain clearing, and system performance testing.

A: Yes, most HVAC installations in Wisconsin require a permit from your local municipality. This includes new system installations, system replacements, and significant modifications. We handle permit applications as part of our installation service. Permits ensure the work is inspected and meets safety codes, which also protects your homeowner's insurance coverage.

A: Air conditioners manufactured before 2010 typically use R-22 (Freon), which has been phased out under the Montreal Protocol and is no longer manufactured in the U.S. Systems made after 2010 use R-410A (Puron), which is still available. If your system uses R-22 and needs refrigerant, the cost can be very high due to limited supply. This is often a strong reason to replace an older R-22 system.

A: High energy bills can result from: a dirty air filter restricting airflow, low refrigerant charge reducing efficiency, aging equipment that has lost efficiency, ductwork leaks losing conditioned air, poor insulation, a malfunctioning thermostat, or a system that is incorrectly sized for your home. We can perform a diagnostic to identify the cause.

A: HVAC system sizing is determined by a Manual J load calculation, which considers your home's square footage, insulation levels, window area and orientation, local climate, and other factors. Bigger is not better — an oversized system will short cycle, reducing efficiency and comfort. An undersized system will run constantly and struggle to maintain temperature. We always perform proper sizing calculations before recommending equipment.

A: Duct cleaning may be beneficial if: you see visible mold growth inside ducts or on HVAC components, ducts are infested with insects or rodents, ducts are clogged with excessive dust and debris, or occupants have unexplained allergy symptoms. The EPA notes that duct cleaning has not been proven to prevent health problems and is not necessary on a routine basis if your system is properly maintained.

A: A zoning system divides your home into separate areas (zones) that can be heated and cooled independently. Each zone has its own thermostat and motorized dampers in the ductwork. Zoning allows different temperatures in different parts of your home, eliminates hot and cold spots, and can reduce energy consumption by only conditioning occupied areas.

A: Many smart thermostats are designed for DIY installation and include detailed instructions. However, some HVAC systems require a C-wire (common wire) that older thermostats did not use, and some systems (heat pumps, multi-stage systems) require specific thermostat compatibility. If you are not comfortable with electrical work or your system is complex, we recommend professional installation.

A: Frozen coils are most commonly caused by restricted airflow (dirty filter, blocked vents, or low blower speed) or low refrigerant charge. When airflow is restricted, the coil gets too cold and moisture freezes on it. If you notice ice on your indoor unit, turn the system off and let it thaw, then check and replace your filter. If the problem recurs, call for service.

A: A brief burning smell when your furnace first starts in fall is normal — it is dust burning off the heat exchanger after sitting idle all summer. This should dissipate within a few minutes. A persistent burning smell, a smell of burning plastic or rubber, or a smell of gas are not normal and require immediate attention. Turn off the system and call for service.

A: Schedule a furnace tune-up in September or October. Replace your air filter. Test your thermostat. Check that all supply and return vents are open and unobstructed. Test your carbon monoxide detectors. Clear the area around your furnace. If you have a heat pump, make sure the outdoor unit is clear of debris. Consider a programmable thermostat to reduce heating costs when you are away.

A: Our maintenance agreement includes a spring AC tune-up and a fall furnace tune-up, priority scheduling for service calls, a 10% discount on all repairs, no overtime charges for emergency service, filter replacement at each visit, and reminder calls to schedule your seasonal tune-ups. Maintenance agreement customers receive the best service rates and fastest response times.

A: We aim to respond to all emergency calls within 2 hours during normal conditions. During severe weather events, response times may be longer. When you call our emergency line at (608) 556-0324, you will speak directly with a technician or dispatcher who will give you an accurate estimated arrival time. Maintenance agreement customers receive priority emergency response.

A: Yes, we work with financing partners to offer flexible payment options on new system installations. Financing options include low-interest and deferred-interest plans. Ask about current financing promotions when you call for your free estimate. We want to make quality HVAC equipment accessible to all of our customers.

A: Yes. Berndt Climate Control LLC is a licensed HVAC contractor in the State of Wisconsin. Our technicians hold EPA 608 certification for refrigerant handling. We carry full liability insurance and workers' compensation coverage. We are happy to provide proof of insurance and licensing upon request.

A: We install and service all major brands including Carrier, Lennox, Trane, Rheem, Goodman, York, Bryant, American Standard, Heil, Amana, Daikin, and Mitsubishi Electric. We are not limited to a single brand, which allows us to recommend the best equipment for your specific needs and budget.

A: Locate your filter slot, which is typically in the return air duct near your furnace or in a return air grille on the wall or ceiling. Note the size printed on the existing filter (e.g., 16x25x1). Turn off your furnace, slide out the old filter, and slide in the new filter with the arrow pointing toward the furnace (in the direction of airflow). Turn the furnace back on. We recommend keeping a few spare filters on hand.

A: If you smell gas, do not operate any electrical switches or appliances. Evacuate your home immediately, leaving the door open. Call your gas utility company from outside or from a neighbor's phone. Do not re-enter your home until the gas company has inspected and cleared it. Then call us for a furnace inspection before restarting your heating system.

Have More Questions?

Our team is happy to answer any questions you have about your HVAC system, equipment options, or our services. Call us at (608) 556-0324 during business hours (Mon–Fri 7am–6pm, Sat 8am–2pm) or use our online contact form.