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Thursday, September 13, 2012

What type of filter should I use in my furnace

How to choose a furnace filter

Information from the Environmental Protection Association:

Most mechanical air filters are good at capturing larger airborne particles, such as dust, pollen, dust mite and cockroach allergens, some molds, and animal dander. However, because these particles settle rather quickly, air filters are not very good at removing them completely from indoor areas. Although human activities such as walking and vacuuming can stir up particles, most of the larger particles will resettle before an air filter can remove them.

Consumers can select a particle removal air filter by looking at its efficiency in removing airborne particles from the air stream that passes through it. This efficiency is measured by the minimum efficiency reporting value (MERV) for air filters installed in the ductwork of HVAC systems. The American Society of Heating, Refrigerating and Air-Conditioning Engineers, or ASHRAE developed this measurement method. MERV ratings (ranging from a low of 1 to a high of 20) also allow comparison of air filters made by different companies.

• Flat or panel air filters with a MERV of 1 to 4 are commonly used in residential furnaces and air conditioners. For the most part, such filters are used to protect the HVAC equipment from the buildup of unwanted materials on the surfaces such as fan motors and heating or cooling coils, and not for direct indoor air quality reasons. They have low efficiency on smaller airborne particles and medium efficiency on larger particles, as long as they remain airborne and pass through the filter. Some smaller particles found within a house include viruses, bacteria, some mold spores, a significant fraction of cat and dog allergens, and a small portion of dust mite allergens.

Filters with a MERV between 7 and 13 are likely to be nearly as effective as true HEPA filters.

• Pleated or extended surface filters

o Medium efficiency filters with a MERV of 5 to 13 are reasonably efficient at removing small to large airborne particles. Filters with a MERV between 7 and 13 are likely to be nearly as effective as true HEPA filters at controlling most airborne indoor particles. Medium efficiency air filters are generally less expensive than HEPA filters, and allow quieter HVAC fan operation and higher airflow rates than HEPA filters since they have less airflow resistance.

o Higher efficiency filters with a MERV of 14 to 16, sometimes misidentified as HEPA filters, are similar in appearance to true HEPA filters, which have MERV values of 17 to 20. True HEPA filters are normally not installed in residential HVAC systems; installation of a HEPA filter in an existing HVAC system would probably require professional modification of the system. A typical residential air handling unit and the associated ductwork would not be able to accommodate such filters because of their physical dimensions and increase in airflow resistance.

Some residential HVAC systems may not have enough fan or motor capacity to accommodate higher efficiency filters. Therefore, the HVAC manufacturer’s information should be checked prior to upgrading filters to determine whether it is feasible to use more efficient filters. Specially built high performance homes may occasionally be equipped with true HEPA filters installed in a properly designed HVAC system.

There is no standard measurement for the effectiveness of electronic air cleaners. While they may remove small particles, they may be ineffective in removing large particles. Electronic air cleaners can produce ozone — a lung irritant. The amount of ozone produced varies among models. Electronic air cleaners may also produce ultrafine particles resulting from reaction of ozone with indoor chemicals such as those coming from household cleaning products, air fresheners, certain paints, wood flooring, or carpets. Ultrafine particles may be linked with adverse health effects in some sensitive populations.

Friday, March 23, 2012

Tankless Water Heaters

I am often asked by homeowners if I recommend tankless water heaters. Some manufacturers claim they can cut energy costs by up to 50%.
So is it time to switch.

Well if you live in Ontario, probably not. ( In my opinion )

There is no question that Tankless water heaters also known as On Demand water heaters are more efficient and have operated in Eurpope quite successfully for many years. This was the major drive in bringing them to North America.
Consumer tests on a variety of on demand heaters have indicated actual average savings of 22% over conventional hot water tank heaters. This translates to actual savings of $70 to $100 /year depending on your energy costs.
The major difference between Eurpope and Ontario is the average temperature of the incoming ground water. In Ontario the ground water can be as low as 35 degF in winter. This means that the temperature rise to bring the water to 120 degF (recommended temperature) is significantly higher than Europe. For this reason high powered burners are required (as high as 200,000 Btu/hr) to provide the flow rates requried for most family homes. Compare this to the average furnace running at 60,000 Btu/hr.

Common problems appear to be:

1. Inconsistant water temperatures particularly under high demand when you are running mulitiple things at the same time.

2. High Up front costs for the unit and for specialized installation.

3. High maintenance costs. Some units require annual flushing (at a cost of $ 130 to $150 )

Bottom line is that with an annual saving of $ 70 per year it could take over 20 years to recover initial purchase cost. Typical lifespan of an actual unit is expected to be 12 to 15 years. Add in the cost of maintenance and the savings more than dissapppear.

If you need a new hot water heater today then my recommendation is to replace you tank unit for now. If you can wait 12 – 24 months then high efficiency tank heaters are being developed and introduced which will be much more efficient.

For more information on How tankless water heaters work:

Thursday, March 22, 2012

Maintenance check list

Inspecting your home on a regular basis and following good maintenance practices are the best way to protect your investment in your home. Whether you take care of a few tasks at a time or several all at once, it is important to get into the habit of doing them. Establish a routine for yourself, and you will find the work is easy to accomplish and not very time-consuming. A regular schedule of seasonal maintenance can put a stop to the most common — and costly — problems, before they occur.
The following website includes a very usefull checklist for a healthy, well maintained home.

Wednesday, February 8, 2012

Measuring Humidity in your home

Humidity is the amount of water vapor in the air. Indoor air increases in humidity as we go about daily living. We add water vapor to indoor air through routine household activities such as showering, cooking, dishwashing and breathing.

We need a certain amount of humidity for comfort and health. However too much humidity often can be seen in the wintertime when homes are closed up and ventilation is limited. Usually it is seen as condensation on windows, musty smells, and mold growth. Low humidity can cause static sparks, dry skin and scratchy nose and throat. High or low humidity levels can also damage wood furniture and flooring.

Using a Hygrometer.
In order to control humidity in your home, it is first necessary to measure it. This is done using an inexpensive instrument called a hygrometer available at most large hardware stores or garden centres. These instruments measure relative humidity (RH). What that means is they measure the amount of moisture in the air relative to the maximum amount of moisture that the air could hold at that temperature. RH is expressed as a percentage. For example if the air temperature is 70 degF and the air contains all the moisture it can hold at that temperature, then the RH is 100%. If the same air contains only half the amount of moisture, then the relative humidity is 50%. RH changes with temperature. Warm air is capable of holding more moisture than cold air.

There are two types of hygrometer, mechanical or electronic and either type is suitable. Hygrometers are relatively inexpensive and not particularly accurate devices so variations of plus or minus 2% can be expected. This is quite accurate enough for most indoor applications. Follow manufacturer’s directions for calibration of the units if necessary.

At any particular time the RH in a home will vary from floor to floor or room to room. Choose the area you wish to measure and leave the hygrometer in that location for a couple of hours before taking a reading. When moving to other locations always allow a couple of hours for the unit to stabilize.

What should the humidity be in my home?
There are no strict rules for humidity levels. Some people are more comfortable at lower humidity levels than others. However, the experts generally agree that maintaining a level of 30% to 50% during the heating season is advisable. I personally prefer the lower end of the scale at 30-40% This will prevent moisture condensation on most double glazed windows and protect wood furniture and flooring. Generally the lower the temperature outside, the lower the indoor RH should be. When outdoor temperature is 14degF (-10 degC) or below then recommended RH is 30 %.

How do I adjust the humidity in my home?

Ideal humidity should be between 30% and 40%.

In summer time humidity can be controlled by using a dehumidifier or running an air conditioner. Either unit will reduce the moisture content in the air. Dehumifiers are not as efficient as central air conditioners and are more suitable for smaller areas or a specific room.

In winter time, high humidity must be controlled by ventilation, increased air flow and reduced moisture generation. If condensation is visible on windows then it is likely that condensation is occurring in other cold areas as well. Warm, moist air travels through the building structure and will condense when it reaches its dew point (a cold surface). Excess moisture plus a food source encourages mold growth.

1. To minimize moisture generation. Always operate ventilation fans when cooking , bathing or showering. Bathroom fans are relatively low flow and should continue to run for a minimum of 20 minutes after showering.

2. Deal with any problems such as a damp basement, roof leaks, excessive plants, excessive aquariums and any other sources of moisture.

3. If you have a humidifier on your furnace. Turn it off or turn the humidistat down to add less moisture to the recirculating air.

If low humidity is the problem:

Air tighten the house. Seal all air gaps where cold outside air can enter the home. This includes vents dryer ducts, electrical outlets.

Install a humidifier. Humidifiers, both stand alone and furnace mounted will increase indoor RH levels. Be aware that they can also be sources of excess moisture and mold in your home so adjustment and ongoing maintenance will be necessary.