Shavitz Heating and Air Conditioning Blog: Archive for March, 2012

What temperature can I turn my A/C on?

Wednesday, March 14th, 2012

With this unseasonably warm spring, I’ve already gotten several calls from clients asking if it is safe to turn on their air conditioners – not the question that I expected during the middle of March! So when can you turn on your air conditioning? A standard system that has the proper refrigerant charge and correct airflow (from good ductwork and a proper fan speed setting on the indoor furnace or air handler) can be turned on at outdoor temperatures at or above 65 degrees. Running a standard air conditioner below 65 degrees and/or with insufficient ductwork or refrigerant charge can significantly reduce the life of the equipment so the best recommendation is to have a trained professional come to your home and perform preseason maintenance to prevent expensive problems in the future and make sure your a/c is running at its max efficiency. Lower electric bills and a cleaner planet, go ahead and hug your polar bear.

If your home or business gets hot even when it’s cooler than 65 outside (multi-unit buildings, lots of east facing windows, or commercial properties), a “low ambient kit” can be installed onto your air conditioner to enable it to operate reliably below 65 degrees. This kit must be installed by a professional and is often specific to each make and model of air conditioner. If your air conditioner is a package outdoor unit (like a rooftop unit) you may be able to get almost free air conditioning with an economizer which will draw in cool outdoor air without running your compressor. The only thing that will be using electricity is the fan motor which uses much less than the compressor. Another great way to lower electric bills and carbon footprint, where’s that polar bear?

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What type of humidifier is best for my home?

Tuesday, March 13th, 2012

A whole house humidifier is the best type of humidifier for your home. They are much more effective and easier to maintain than individual portable humidifiers. The standing water in portable humidifiers can also lead to mold/bacteria growth if not cleaned or operated properly. But what type of whole-house humidifier is best? The answer depends on how much humidity your home needs.

The three most common types of whole house humidifiers are evaporative pad humidifiers, steam humidifiers, and spray/atomizing humidifiers. A pad humidifier operates by blowing warm air over an evaporative pad that has water trickling down it. The warm air evaporates and absorbs the moisture into the air. Steam humidifiers use electric probes to boil water and inject the steam into the air stream. Spray or atomizing humidifiers have a fine nozzle which sprays a mist into the air stream.

A spray humidifier is the least expensive but also the least common. These humidifiers must have very clean water to prevent minerals from plugging or partially plugging the nozzle. A partially plugged nozzle can change alter the mist into a stream of water that doesn’t evaporate and can cause leaks and water damage. For this reason they typically require annual nozzle replacements and often require an inline water filter that also should be replaced annually.

The most common humidifier is the pad type humidifier. When installed on a properly sized (and preferably two stage) furnace, they are capable of humidifying most homes. They are fairly easy to install, service, and maintain (simply change the humidifier pad at the beginning or end of each heating season). They come in two types, power and bypass. A power humidifier mounts to the side of the supply ductwork and has a built-in fan to draw air across the pad and blow the humidified air back into the ductwork. A bypass humidifier has a bypass duct that utilizes the furnaces own fan to recirculate some of the warm supply air across the humidifier pad and back into the return ductwork. Since bypass humidifiers do not have a built-in fan, they have less things that can break but do require the manual bypass damper to be opened in the winter and then closed in the summer. In some cases bypass humidifiers can exacerbate existing undersized ductwork problems, so make sure your installer is well trained and checks that your ductwork is properly sized so that your furnace can get the proper airflow.

Steam humidifiers are the most effective, but are more costly to install and operate. If you have high end wood furniture, flooring, have a large home, or need precise humidity control, steam humidifiers are the best option. They require a dedicated electrical service and need annual maintenance. Some simply require annual cylinder replacements while others need heavy duty cleaning to scrape away build-up of mineral deposits that inhibit effectiveness.

All three humidifiers should be operated via a humidistat which can be adjusted to the desired humidity setting and will automatically turn the humidifier on and off as required.

If you are curious about which type of humidifier is best for your home, feel free to call us!

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What humidity level should my home be at?

Tuesday, March 13th, 2012

Many people ask me what the proper humidity level in their home should be. While the humidity level each home can handle varies based on the home’s insulation level, window quality, and outdoor temperature, the ideal humidity range is 30-55% relative humidity. Achieving proper humidity levels is very important for your health and keeping your home in good condition.

Humidity levels that are too low are uncomfortable (dry, itchy skin), can be unhealthy to asthma and allergy suffers, will warp and crack wood and furniture, and can result in higher heating bills. Low humidity levels make you feel colder so you compensate by setting your thermostat higher and increasing your heating bill – it’s not the heat it’s the humidity! It can also increase moisturizer and lotion bills!

On the flip side, humidity levels that are too high can promote mold, bacteria, virus, and dust mite growth, can also be bad for asthma and allergy suffers and will also damage wood. During the winter, high humidity levels will also lead to condensation on windows which can lead to mold growth or water damage.

In the summer your air conditioning system will dehumidify your home, often pulling gallons of water out of your air every hour! Sometimes a stand-alone dehumidifier may be necessary, especially in musty basements. In the winter, your home will need a humidifier to add humidity to that dry winter air. Your humidifier is most commonly hooked up to the “humidistat” which is a dial or digital display on your wall or return ductwork which will allow you to control the humidity. A whole-house humidifier that is tied to your ductwork will be the healthiest and most effective humidifier. Watch out for stand-alone humidifiers that have standing water which could promote bacteria growth.

When setting the humidity in the winter, I always recommend to set the humidistat to the highest humidity level the home can support (up to 55%). Remember, higher humidity levels are healthier and lower utility bills because they are more comfortable. However, as it gets colder outdoors, the windows and window frames of your home will also get colder and you may get moisture condensation and even frosting. This is a sign that your home can’t support that level of humidity and you will need to lower the setting on your humidistat. Replacing windows or window frames with better insulated windows might also be something to consider down the road.

Stay tuned for the next posting which will discuss the different types of humidifiers and which one is best for your home.

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Holy Shavitz Stat Squad

Wednesday, March 7th, 2012

Check out our Shavitz Stat Squad – just click the thermostat at the top of this page next to our logo. We had a little fun with it and hope you like it. If you have any clever drawings of your own unique thermostat character, send them to It may end up on the site!

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