​Tips from the Pro's

Staying with our heating season theme........We are often asked by our heat pump home owners, "what's the difference between auxiliary heat and emergency heat?" 

Most all ducted central heat pump systems have some type of auxiliary heat source. It could be a gas/propane furnace or electric heating elements often referred to as heat strips, either way auxiliary and emergency heat is the same heat source, gas or electric. The difference is how it's used. Depending on the type/brand of thermostat, switching the system or mode to emergency heat activates a different relay that "locks out" the normal heat pump function and only utilizes the auxiliary or "backup heat" source. This in most cases is only needed when there has been some kind of a failure with the outside portion of the heat pump system. In the case of a conventional heat pump with electric auxiliary heat leaving the system mode switch in the normal heat setting will allow the system to run as designed. When the temperature drops outside to the point where there is not enough heat in the air to satisfy the demand inside the home, electric heating elements will be sequenced on and off to provide additional heat. This will in most cases take place automatically and is done in conjunction with normal heat pump operation. If the heat pump system utilizes a gas/propane furnace a separate outside air temperature sensor is used to decide when its too cold to operate the normal heat pump and when its time to shut if off and utilize the gas/propane furnace. This type of "hybrid heat pump" is considered more efficient in that it does not continue to use the outside portion while it is struggling to exchange heat, it simply shuts it off and quickly brings the home to set point using the furnace. This changeover though is not quite as seamless as bringing on electric heating elements, the outside heat pump portion must shut down, while the blower continues to run and the furnace must begin it's start up procedure before the flame comes on allowing for 30-45 seconds of slightly cool air. The outside heat pump or refrigeration system cannot run for any length of time while the gas/propane furnace runs. So.......... with all this said it's best to just leave your heat pump system mode set to normal "heat" and allow the system/thermostat to control the auxiliary heat as it was intended. If a failure in the outside unit takes place your service company may tell you to go ahead and switch it to "emergency heat" until the repairs can be made otherwise it should just stay set for heat. Stay warm and give us a call, (302) 260-4228 for all your heating system service or repair needs!!

​M.L. Building Technologies

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Heating & Air Conditioning

For All Your Heating and Air Conditioning service and repair needs 302-260-4228                 

Monday-Friday 8 AM to 5 PM Saturday  8 AM to 12 Noon

Filters 101!

There seems to be a fair amount of confusion out there about filters, MERV rating, change intervals, etc. 

First, the MERV rating, Minimum Efficiency Reporting Value is based on ASHRAE 52.2 Standard. This refers to how well the filter is able to catch and hold pollutants in the air of your home. The higher the MERV number the more efficient the filter is at capturing those pollutants. Here is a breakdown on some of the typical MERV ratings for residential HVAC systems:

MERV 1-5, basic protection for dust and airborne dirt particles, typically these are the disposable fiberglass filters.

MERV 6-8 Good protection for smaller particles ranging from 3-10 microns, including mold spores, hairspray particles, allergens and pet dander.

MERV 9-12 is a superior filter for residential use and will trap particles from .5-3.0 microns including Legionella bacteria.

How often should filters be replaced? This largely depends on the homes occupants, do you have allergies or respiratory issues, do you have pets, do you like to have the windows open during the Spring and Fall or do you go from the heating season straight into the cooling season with home closed up, do you have small children? If the answer is yes to any of these questions you may want to consider a higher quality, higher MERV rating filter and replace them every 8-12 weeks, if not the middle option MERV rating of 8 and a six month replacement schedule would be sufficient.

Remember the best filters in the world do absolutely nothing in a residential system when it is not running!! Many modern thermostats have a "Fan programing" feature that we encourage our clients to check out. It generally runs the system fan for 15 minutes each hour in increments to circulate the air without running the heat or AC. This feature not only allows the filters to do what they are supposed to, it also helps to reduce warm and cool spots in the home.

M.L. Building Technologies your Indoor Air Quality Specialists!!

(302)260-4228


It's Heating season and hopefully everyone has had their heating system serviced/checked/cleaned for the cold weather.........right?

Depending on the weather and  what you normally keep the thermostat set to, you may want to check and or replace the filter/s mid way between your Fall/Winter service and your Spring service. We usually recommend at least checking them every 90 days. If you have pets or small children you may just want to go ahead and replace them. 

Proper system operation, good indoor air quality all start with good quality clean filters. The primary purpose of the filters is actually to help protect the equipment, much like a cars air filters' purpose is to protect the engine from harmful dirt. Your homes filters' secondary purpose is to help provide cleaner air for the homes occupants. Clogged or dirty filters lead to higher than normal blower motor amperage draws, reduced airflow to rooms, and in the case of heat pumps can also significantly increase system refrigerant pressures, leading to premature component failure.

If you have a gas/propane furnace the reduced airflow can cause high temperature safeties to trip  shutting the equipment down when you need it the most. Comparably speaking replacing filters regularly is inexpensive and can go a long way towards keeping the equipment running efficiently for years, not to mention what it can do for your's and your families indoor air quality. M.L. Building Technologies would be happy to set up a regular filter change schedule for you, call (302)260-4228 to find out more information!