HVAC Problems Solved

HVAC Problems and Settling for “It’s Always Been That Way” Doesn’t Have to Happen.

Don’t get discouraged, give up or decide to just live with it.  Here are some issues we frequently see.

What You Can Check If You Have No Heat Or Air Conditioning

First check your circuit breakers and try resetting the circuit board.  Check to make sure the batteries in your thermostat are still good.  Check your filter, if it’s really dirty it can shut the system down.  If none of this resolves the issue, call us.

Why Your Furnace May Not Be Working

There are several reasons why your furnace may not be working. Most modern furnaces have a diagnostic light that aids in determining what area needs further diagnosis. Here are some common reasons for breakdowns:

Dirty flame sensor: the flame sensor is located between the burners and the opening of the heat exchanger. It senses the flames. Over time carbon will build up, reducing the sensitivity of the sensor. It can be cleaned, seldom does it need to be replaced.

Ignitor cracked or broken: This will need to be replaced. As the ignitor gets older and has more wear and tear, the electrical resistance becomes higher making it harder for electricity to pass through. With age it becomes white and chalky looking.

Drain line plugged: this can be removed and flushed, or worst case scenario, may need to be replaced. High efficiency furnaces produce water, over time the drain line can grow algae and plug the line causing water to back up into the furnace.

Dirty air filter: This should be checked monthly and changed as needed. The air filter traps particles and prevents them from getting into your motor and furnace parts.

All of these problems and others can be avoided with an annual clean and check.

Why You Should Get Your HVAC Equipment Cleaned and Checked

Cleaning your HVAC equipment helps avoid problems leading to breakdowns and may reduce energy costs.  Not only do all manufacturers recommend annual cleanings, but are now asking for service records when certain warranty claims are made.

How Often Should Your HVAC Equipment Be Cleaned?

You should have your HVAC equipment cleaned once each season to ensure your equipment is operating at peak efficiency.  Typically furnaces and boilers are serviced each fall before the heating season; Humidifiers are cleaned at the same time as the furnace; Air conditioners each spring before cooling season.  Removing build up, debris, inspecting and calibrating your equipment will help avoid problems and extend system life.

Filter Schmilter

Yes it’s one more chore to be done, but filter maintenance helps keeps your system efficient and can prolong system life.  Your filter should be checked once a month.  If you see dirty build up, and you have a disposable filter, replace it.  It’s a good idea to keep 2 or 3 on hand.

Dirty filter

Dirty filter

If you have a permanent filter…
Recommended method:  Spray it with an all purpose cleaner, let sit for a minute or two, then rinse with high pressure water.
Alternative (or its-wintertime-for-goodness-sake!) method:  Vacuum with hose attachment – all vertical strokes, then horizontal strokes.

If this is just one more thing you don’t have time for or something you don’t care to do, we can help you with that.

Cleaning: How to Tell You’re Actually Receiving One

a/c before cleaning

a/c before cleaning

Its a bit of a mystery – Are you receiving what you’re supposed to? And how can you tell?

a/c after cleaning

a/c after cleaning

Your service technician should ask you if you have any problems, questions or concerns and be able to provide knowledgeable answers and solutions. Your equipment and comfort are important and the technician should give you the sense that they care about both.

It takes a good 45 to 75 minutes to thoroughly clean an air conditioner or furnace (boilers may be longer). This time is needed to remove, clean, inspect, re-install and calibrate parts of the system. This time should be devoted to working on your system.  When the service technician walks in the door, he should bring these necessities:

  • Assortment of hand tools
  • Digital meters: tells how much power the equipment is using
    Drop cloths: protect your home or business and provides a place to put tools down
    Digital manometer: a tool for measuring gas and air pressure
  • Temperature probes
    Flashlight and mirror: great tools for inspection
    Checklist of parts to be inspected; data log for recording information
    Cleaning solution and rags
  • Shop vacuum: has a filter to trap very fine particles (furnace/boiler cleaning)
  • Furnace brush (furnace/boiler cleaning)
    High pressure hose (air conditioner cleaning)
  • Spray bottle of a/c coil cleaner (air conditioner cleaning)
    Correct size humidifier pad and hygrometer for measuring humidity (humidifier cleaning)
  • Combustion gas analyzer: a machine that measures gas levels and equipment efficiency before and after cleaning

If you’re making the effort and investment to have your system cleaned, good for you (and your equipment).  You should get what you’re paying for and what your equipment needs.

Should You Have Your Air Ducts Cleaned?

According to the U.S. Environmental Protection Agency (EPA)“Knowledge about air duct cleaning is in its early stages, so a blanket recommendation cannot be offered as to whether you should have your air ducts in your home cleaned.” Click here to read more about air duct cleaning from the EPA

Why does my furnace and air conditioner bang when it comes on or off?

The ductwork is undersized, delivering or receiving less than needed airflow to the blower motor. Sometimes blower speeds can be adjusted which reduces this problem.   Otherwise, the ductwork needs to be calculated and additional ducts may be needed.

If Your Furnace Is Loud…

If your furnace has always been loud, it’s most likely due to improper design and installation. Furnaces should be designed according to the air flow and heating load needed for the house.  Unfortunately, many contractors determine size using a rule of thumb, or install the same size as the previous system, and don’t do the proper engineering to determine what size furnace, air conditioner and duct work is needed.

If it’s a new problem, the blower motor could be going bad and may sound like a squealing bearing or it could be how the furnace is igniting. If you hear a BOOM when the furnace ignites then the furnace needs to be cleaned.

Why Does My Furnace or Air Conditioner Whistle?

Too much air flow is going through the return grill. The grill or ductwork may be too small or the blower motor is not calibrated for the needed air flow. Don’t live with it, this can be addressed by having the ducts and grills sized for the airflow needed and/or adjusting the blower speed to recommended settings.

Why Doesn’t My Humidifier Work?


Furnace humidifier

Many times people don’t think their humidifier works, when all the system needs is a proper cleaning.  Flushing lines, cleaning and inspecting internal parts is required annually. The humidifier pad should be changed once a year or more depending on the hardness of the water. If your humidifier is not level, it’s not working properly (this would be addressed separate from your cleaning).

Noises and Hot and Cold Spots: Not Just the Way It Is

Whistling or banging noises, hot and cold spots, a filter that is hard to remove, excessive part replacement and high utility bills are all symptoms of insufficient air flow.  Insufficient air flow can be caused by an over-sized system, undersized/restricted duct work or a dirty system.  Most of the time your existing duct work can be modified without cutting into drywall.

Some simple things you can do to improve air flow:

Duct sealing with metal tape

Duct sealing with metal tape

1. Change your filter regularly. A dirty filter can starve a furnace or air conditioner for air.
2. Make sure all supply and return registers are not blocked.
3. Adjust air flow dampers in supply ducts (we can show you how).  This will reduce air flow in places that get too much, forcing air flow elsewhere.  For example a dining room that is not frequently used may be receiving too much air flow.
4. If you have high/low placed returns grills, adjust for the seasons. In the summer open high returns and close low returns.  In the winter open low returns and close high returns.
5. Seal your ducts using metal tape or mastic adhesive or have professionally done.  Seal every joint and fitting to prevent air from escaping or entering your duct system.
6.  Have your furnace and air conditioner professionally cleaned and inspected annually.

Properly designed, installed and maintained equipment and duct systems can achieve uniform temperatures and air flow with minimal noise.  Learn more about duct sealing from Energy Star here.   A system with good air flow will not have to work as hard, should last longer and will save you money and your sanity.

Should HVAC Vents Be Closed in Rooms That Aren’t Used?

No, you should not close the vents.  You still need to partially condition the room.  Closing the vents causes temperature extremes which are hard on the house, causing wood and drywall to expand or contract.

How To Reduce Your Heating Bills

  • Have your furnace cleaned annually.
  • Install a programmable thermostat and use the program.
  • Seal HVAC ducts.
  • Install a humidifier. Humidity will make you feel more comfortable at lower temperatures.
  • Insulate or add more insulation to ducts if they go through an attic or crawl space.

It Doesn’t Have To Be That Way (even though it’s always done that)

Your indoor climate should be comfortable. It should be easy to maintain a desired, even temperature throughout with no bothersome noises. If not, there’s something going on that can be addressed.  If you have an indoor comfort questions or concerns, talk to your service technician.  If they don’t take the time or cannot fix it, find someone who can.  It’s rare that there is not a workable solution to your problem.

System Size: Bigger is Not Better

Many people, even contractors, believe a bigger heating or air conditioning system gives more power but instead it creates many problems. An over-sized system will run frequently for shorter intervals causing only partial heating and cooling.  It is more prone to breakdowns, noise and higher utility bills.  It will cost more upfront and in the long run to maintain.  An over-sized furnace or boiler can lead to unsafe conditions such as carbon monoxide leakage. An over-sized air conditioner will cool quickly but will not pull out the humidity.

Your system should never be sized based on what size you currently have or a rule-of-thumb estimate (an unfortunate industry shortcut).  A heat loss/heat gain calculation should be performed to determine what is the right system size.  Read more about how an over-sized furnace wastes money and energy here (from Green Building Elements)

Why Your Furnace May Be Leaking Water

A furnace leaking water may be due to a plugged drain line.  The drain line can be removed and flushed or may need to be replaced.  High efficiency furnaces produce water, over time the drain line can grow algae and plug the line causing water to back up into the furnace.

Humidifiers can also be the cause of leaking water. As humidifier pads age, pieces of the pad can break off and go into the drain line and plug it.  The humidifier also needs annual maintenance at the same time as the furnace.


Zone damper round

Round zone damper

Imagine walking in the door and flipping one light switch for your entire house; that’s how most heating and cooling systems operate.

Zone damper rectangle

Rectangle zone damper: opens/closes the duct according to input from the thermostat.

Zoning is creating specific, custom climate areas within a home or facility. You can have a whole floor,  just one room, or a combination of rooms as one zone.

Zoning can be achieved in two ways:

1) A dedicated system for each zone
2) Electro-mechanical dampers and thermostats which direct airflow as you wish.

With method two for example, if you have a two story house and want a zone on each floor, a thermostat is required on each floor, ductwork is divided between the two floors, and electro-mechanical dampers are installed in the supply ducts.  Many variables factor into the time and cost.

The big benefits of zoning include precise comfort control and less utility usage (and less guilt for turning up the thermostat). You can crank up the heat in one zone without affecting anywhere else.  Generally smaller equipment is required.

Thermostats: Way Beyond Just Hotter or Colder

Honeywell Prestige IAQ

Honeywell Prestige IAQ

Thermostats today offer an array of features including:

  • Reminders for system maintenance, filter change and humidifier pad replacement
  • Automatic controls for humidification, dehumidification, ventilation, air cleaners, UV lights
  • Internet access: Get alerts when your system malfunctions or is not within your specified settings; reminders (like above). Access and adjust your thermostat from anywhere on your smart phone.
  • Remote sensor: This accessory averages temperature readings in up to four locations and adjusts run time to create more even temperature. It can also remotely sense temperature anywhere in the house and adjust baseline temperature to match.
  • Seven day programming with up to four temperature settings per day; vacation settings

Despite all the high tech bells and whistles, most of the advanced-featured thermostats are user friendly and can walk you through programming in plain language. Or if this is too fancy for you, just hit one button and you’ve got a non-programmable thermostat.   Use the interactive tool from Energy Star to learn how to program a thermostat here

Crack in heat exchanger

Crack in heat exchanger means potential hazard and may be time to replace

How To Buy a Furnace or Air Conditioner: What You Need To Know

It is very important to remember that the system is NOT a finished product when it comes off the assembly line like a car or a refrigerator.  The design and installation method is key to a successful install.   If equipment size is determined from using only the square foot or looking at the current name plate, then it is not sized, it was replaced with what you have now and there is a good chance that some or most of your concerns will not be addressed.  Get a heating and air conditioning installation bid comparison checklist here from Energy Star

The sales person should have the proper investigation tools:

  • Tape measure
  • Flashlight                                                                                                                                                                                                                                                                                                                 
  • 6 in one screwdriver
  • Camera
  • Heat loss/heat gain software
  • Note pad or digital note pad
  • Certificate of insurance

The design phase includes performing a heat loss/heat gain calculation.  This calculation includes the volume of area being conditioned; the orientation of each wall; sizes of each window and door; insulation in wall, ceiling, and floors.  If there is a 2nd floor or attic. The type of attic: vented, unvented, encapsulated or several other types.  Floor type: above a crawl space that is open, crawl space that is closed, basement below grade.  Where the home is located is very important too; Chicago’s winter is different than Houston’s.

Other design considerations:

  • The existing duct system needs to be measured and calculated for amount of air flow it can move according to manufacturer specification.
  • Supply and return grills counted with sizes and location.
  • Check electrical panel for proper size and type of breaker(s)
  • Your comfort concerns need to be addressed:  temperature, humidity, dehumidify, noise, allergies, dust, safety. Location of equipment inside and outside.  The temperature you keep your home is also critical. Systems when designed properly will achieve your temperature on designed degree days (these are the coldest or warmest days based on an average over a 10 year period).
  • It takes me about an 90 minutes to get all the above information, and I still haven’t given a price yet.

Be leery of:

  1. Contractors who are in and out, quickly and write their proposal on their business card.
  2. Contractors who say “I done lots of this model house it needs to be this size”.
  3. Businesses who have been around for a while but cannot give you referral and pictures of their recent work.

In my seventeen years of servicing, installing and selling HVAC equipment, I have seen very few homes/businesses that have made me go “wow they did a nice job”.   Heating and cooling equipment is a major investment and the process should be thorough and specific to your environment, needs and preferences.  Energy Star 10 Tips for Hiring a Heating and Cooling Contractor

Air Conditioning Covers: Not a Good Idea

Air conditioning covers are not recommend for several reasons:

  1. During the colder months rodents and other small animals are looking for shelter from mother nature; by installing a cover on the a/c you just gave them a home. If rodents are living in the equipment, then there is a
    Mouse house found under an a/c cover

    Mouse house found under an air conditioner cover

    good chance they will be chewing on the wiring and leaving deposits.

  2. Covers may trap moisture inside them which would cause the metal to rust and deteriorate.
  3. If you forget to take it off the air conditioner, the a/c will overheat and burn out.

If you are worried about the leaves falling in – don’t. When your a/c is cleaned the necessary panels are removed in order to clean any debris inside. Without the cover the drain holes at the bottom of the a/c won’t get clogged.

Does It Make Sense To Turn Down/Up The Thermostat When You’re Not Home?

The answer is both yes and no. Most of the year I would recommend adjusting the thermostat except for the days that are extremely hot or cold (ie +95 and -6). On these days I would recommend keeping one temperature in the home because your furnace and air conditioner should be designed to deliver a certain temp at these extremes. If you are raising the temp up and down and it is 97 degrees outside the air conditioner does not have enough capacity to cool the home any further. It will only maintain the current temperature setting until the air outside cools down.

Information is Power

To gain more of both, click here for tips on arming yourself with information on maintenance, buying a new system, HVAC services and more from This Old House.





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