Tuesday, December 28, 2010

Heating and cooling sytem efficiency and cost

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If you're like me you tend to view energy efficiency both in terms of monthly energy usage and cost; that is to say, the total amount of energy you use as well as the total amount of green stuff you fork out each year to heat and cool your home or office. So before rushing out to purchase the latest energy efficient appliance to heat or cool your home keep a few thoughts in mind:

The total amount you pay to heat or cool your home or office can be a lot more than just how much you pay for utilities. Consider other costs that are direct expenditures to you. These should be factored into estimates for your total yearly cost and may affect your year-end utility balance sheet.

Repair and maintenance costs should be high on the list of items you consider when purchasing that new HVAC system from a contractor. Sure that high efficiency unit has all the latest technology with its accompanying bells and whistles but has it been field proven yet? The literature states that there is a lifetime warranty for many components but will the heating contractor or manufacturer be around if something were to go wrong? Do they have a track record of honoring their labor warranties? One expensive repair out of warranty will cause the true efficiency, from a pocket book perspective, to go way down.

Initial installation cost factors large in pocket book efficiency. Today we have high efficiency boilers, wood burners, geothermal heat pumps, furnaces and more. Most of these boast efficiency ratings in the low 90's and up. So lets say you currently spend an average of 200 dollars per month for five months in the winter. If your current system performs at 60% efficient ratings you can anticipate a net energy gain of 30% if using a 90% efficient system. In terms of dollar savings, that comes out to approximately 300 dollars per year. Keep in mind energy costs are predicted to continue increasing so those savings would expand each year.

Now take a look at your initial installation investment. What will the payback time be? Are some heating solutions less expensive than others? Are some fuels less expensive than others? There are also many renewable energy sources available today. One such heat source, wood, has become very popular today and boasts some of the lowest installation as well as monthly costs. Since it is renewable it has the potential to be very eco-friendly as well, however, this form of heat requires more user involvement too.

There are a lot of trade-offs to consider when evaluating the different types of high efficiency heat but it is worth taking the time to choose the type that makes the most sense to you. There are bound to be perfect matches for your lifestyle. As in many areas of life, the least expensive choices usually require the most maintenance, but don't let this deter you from getting the most out of every btu and dollar used to heat or cool your home or office.

HVAC-R Community College Instructor
Owner Four Seasons Heating and Cooling

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Sunday, December 26, 2010

A cool and hot topic: Follow our posts

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About Energy Efficiency and Sustainability

Improving energy efficiency is the first and most important step toward achieving sustainability in buildings and organizations. Energy efficiency helps control rising energy costs, reduces environmental footprints, and increases the value and competitiveness of buildings.

When people ask us about sustainability, we tell them it means getting the most out of every single unit of energy, water, materials and resources used in their buildings.Why? Because it’s how we use resources in a way that meets the needs of today without compromising the ability of others to meet their own needs tomorrow.

From Johnson Controls


Diagnosing Furnace Problems

How to diagnose a furnace problem? most furnaces today have an Integrated Furnace Control (IFC) board that lends a hand in figuring out many common problems.  However, having a proper understanding of Furnace and Air conditioning fundamentals is always the best place to start your furnace repair journey.  In subsequent posts we’ll take a look at each component of a high efficiency furnace and detail their function within the big picture of furnace operation; but first let’s talk about that scary, complicated, and sometimes intelligent IFC board.

The Integrated Furnace Control board has been symbiotic to the evolution of high efficiency furnaces.  As high efficiency furnaces developed, the need for additional components necessitated the development of intelligent monitoring and control systems.  It may be hard to imagine now, but the introduction of a computer-like component within the furnace was a major paradigm shift for service technicians who were unfamiliar and intimidated by electronics.  Many of us (I belong to this class) wondered if our days of heating and cooling repair were numbered. 

Fortunately the manufactures did a good job of educating service technicians that were willing to attend technical training seminars on how and why IFC boards work.  The IFC boards of today have some very reliable diagnostic tools that have, in some ways, made our jobs easier.  Most of these boards have some variation of blinking lights that point to an error code on one of the labels of the furnace. These labels are usually located on one of the removable panels on the front of the furnace.  Though there is still a need for sound technical knowledge, the repair technician of today quite often finds themselves in and out of service calls within minutes, thanks to the diagnostics of the IFC board.

Written by Randy

Friday, December 24, 2010

Taking back the moisture

How much moisture does outside air possess?  This question has a few answers.  The first question that should be asked before giving an answer is "what is the temperature outside?" A given quantity of air will occupy a certain volume at standard atmospheric pressures and temperatures.  Double the temperature and allow the space that this quantity of air occupies to increase so that the pressure of the air remains at standard atmospheric values, and the space the air occupies will approximately double.  This is the reason unconditioned air in your home (no humidification) is relatively dry in the winter.

Very cold outside air at standard atmospheric pressures contain much less moisture per given volume of air than warmer air.  This is specifically true when cold and warm air at the same relative humidity levels are compared. Relative humidity is a measure of how much moisture a given quantity of air contains compared to how much moisture that same quantity of air could potentially hold.  As an example, say a 100 cubic foot volume of air at 70 degrees has a relative humidity of 50% and contains 1 cup of water.  At 100% relative humidity this same volume of air would contain 2 cups of water. Now lets take a look at why our homes are so much drier in the winter.

Let's say the outside air is 0 degrees F and is at 20 percent relative humidity.  If we take a 100 cubic foot sample of this air and assume it holds 5 ounces of water when it is at 0 degrees and 20 percent relative humidity, what will happen to that air when we bring it into our house and raise the temperature to 70 degrees?  First of all, the 100 cubic foot space this air occupies will increase dramatically when it is heated to 70 degrees.  Instead of occupying 100 cubic feet this same quantity of air will occupy a much greater space.  If air is allowed to expand, heated air will always occupy a much greater space.

Hopefully the picture is starting to become clear.  Let's go back to the outside air that contained 5 ounces of water at 0 degrees.  Now that we've brought the air inside the home and raised it to 70 degrees lets assume it occupies 200 cubic feet of space.  As you can see, five ounces of water contained within a much larger 200 cubic feet of space thins the solution out considerably.  All of those airborne water molecules are much farther apart and the air begins to feel dry.  Also the relative humidity of the air has decreased significantly, since not only has the air expanded to a much greater volume, but also warmer air is able to hold much more water at similar volumes as cold air.

Our homes are continually bringing in outside air to make up for air that is lost to the outside. There are many reasons our inside air is expelled to the outside such as exhaust from hot water heaters and furnaces.  When new air from the outside is brought in it immediately expands and the relative humidity of that air goes down.  This is why we need humidification in the winter.

Written by Randy

Sunday, December 19, 2010

Furnace sizing

Sizing furnaces today: Large or Small?

Just like the cars of old the conventional wisdom of the sixties and seventies was “the bigger the better” when it came to furnace size.  But what is the best approach when sizing a furnace?  Many customers seem skeptical when given the advice to size their furnace as small as possible.  Certainly the furnace size will need to be adequate for that below zero January day but is it in your best interest to have a “454 Suburban” in your basement?

Unless there’s some inherent satisfaction personally gained from watching your thermostat rise five degrees per minute you should probably consider the benefits of sizing your furnace on the small side.  Let’s take a look at some of the reasons for sizing “small”. There are three very important ones:

1- Efficiency:  Consider the fuel economy your vehicle delivers under these different operating conditions (highway and city).  Just like automobiles your furnace is the most inefficient during stop and go operation.  The larger the furnace the more often it will cycle and, just as in city driving, the more inefficient it will be.  True the monster furnace in the basement will raise the temperature rapidly but it will tend to cycle more frequently as well. Where as the smaller furnace will remain in operation longer (highway driving) trying to achieve the set-point on the thermostat.

During these longer run times a furnace operates at peak efficiency. The reason for this is that every heat cycle begins with an ignition phase and subsequently a heat exchanger warm-up phase.  While the furnace is in the heat exchanger warm-up phase the indoor blower is off; and consequently there is little heat added to your home.  Before the blower motor turns on, a portion of the heat added to the heat exchanger goes right out the flu and not in your house.  Each heat exchanger warm-up phase is accompanied by a loss of heat energy to the atmosphere.  Therefore, just as in highway traffic, the less a furnace cycles, (starts and stops) the more efficient it will be. If you could heat your home with a pilot light running continually from October to April your fuel bill would be the lowest possible.

2- Comfort: Not only is your furnace inefficient during stop and go operation, it is also uncomfortable.  That furnace we described earlier in your basement, the 454 Suburban, will certainly raise the temperature in the room but consider what that means.  Unlike the thrill of going from 0-60 miles per hour in four seconds there is little excitement in going from 70 to 72 degrees instantaneously.  In fact when a furnace is sized too large the extra heat mass stored in the heat exchanger will tend to “overshoot” the set point of your thermostat.  When the room temperature is high enough, the thermostat will turn the burners of your furnace off, but the extra heat contained within the heat exchanger will continue to heat your room until the indoor blower removes all the heat stored in the heat exchanger. During this time period your room temperature may rise higher than the temperature your thermostat is set at. This will also add to your discomfort since you will experience greater temperature swings- Fun in sports cars but not in your home.

3- Noise: Larger furnaces are usually louder.  This is because blower motors for larger furnaces are also larger since they are required to move more air.

The bottom line is: If you want excitement-Buy a sports car.  If you want comfort    and efficiency-Buy a small furnace,

Written by Randy

Friday, December 17, 2010

Radiant heat versus forced air

Radiant hot-water-heat has made somewhat of a comeback recently. Many people believe this form of heat is the most comfortable and efficient on the market.  Radiant floor heat, another form of hot-water-heat, is remarkably comfortable and may even allow you to dial the thermostat down a bit.

The biggest disadvantage to radiant heat is probably the difficulty in adding air conditioning to your home. So before you decide on the type of heat you would like to install, it would be a good idea to consider whether or not you plan on installing A/C. A/C will most likely be possible for homes with radiant heat, however, the expense of an A/C install will be considerable.  If your goal is to have the most comfortable heat available I suggest radiant. If your budget ultimately determines the type of heat your home ends up with then forced air or even a wood-burning stove may be the choice.

Consider this other aspect of radiant heat.  Boiler manufactures have produced high efficiency condensing boilers for some time now.  With efficiency ratings of 95% and more, consumers have a great opportunity to choose a heat that is not only very comfortable, but also now very efficient.  Added to this is the comfort level of radiant heat that quite often allows a homeowner to lower their thermostat setting; providing for even greater savings on their home heating bill.

So if you are in the market for a new heating system, make sure you give radiant heat a second glance.  You may find a warm friend for those cold northern nights.

Written by Randy

Friday, December 10, 2010

Furnace accessories

There are a great deal of furnace accessories for the home. Two that top the list are the high efficiency filter and the whole house humidifier.  Both of these products will add a measure of efficiency and comfort to your indoor quality of life.  Let’s talk about humidifiers. 

Quite often when a whole house humidifier is installed on an existing furnace the homeowner is able to lower the thermostat setting by two or three degrees while maintaining the same level of comfort.  The same principal causes us to feel hotter on humid days in the summer.  At certain temperatures, humid air causes us to feel warmer.  So bring the tropics with all of its warm humid air to your winter home.  Maybe even plant a palm tree and imagine how terrible it must be for all of those residents living in places like Michigan.

Here’s how to start.  Call a reputable heating contractor for a quote to install a by-pass type whole house humidifier.  GeneralAire makes a family of very fine humidifiers of this type.  Second, make sure you do this before January.  January is known for its very dry air and is also the time of year that most folks who suffer from dry skin and respiratory problems really begin to notice the lack of moisture in the air.  Another bonus of doing this in December is that it can qualify as a Christmas present for the whole family.

Written by Randy

Thursday, December 9, 2010

Heating repair

Newer furnaces may be more efficient but never let anyone fool you into thinking they are more reliable. They are certainly more reliable now then they were during the bleak years of high efficiency furnaces manufactured during the eighties, but there are still quite a few furnaces from the fifties and sixties chugging along out there. Oh but those buggers were inefficient!

How many times have we heard how reliable grandpa’s truck was?  “You see, the steel was so much thicker back then, and the workers really cared about craftsmanship.”  That was of course before the day of electronics under the hood too.  But as we know, things have all changed and that generation is no longer producing our manufactured goods. 

Before we buy into this theory we should probably take a look at how many vehicles of old truly registered odometer readings past 300,000 miles.  What I am getting at is that the old theory that electronics and new manufacturing techniques have somehow caused the downfall in vehicle reliability may be slightly skewed.  Does anyone remember the semi-annual ritual of changing caps and points and rotors? 

Of course the reliability factor is only part of the argument.  Think about all of the cool features our new vehicles possess such as antilock breaks, air bags, and electronic fuel injection.  But having said all this I am still standing by my first few sentences, mostly because the eighties were such a blight on the reliability of our manufactured goods.

But is it possible that the eighties might have an excuse?  I believe they do.  Every new technology has its learning curve.  Think about how fast things were changing in the eighties.  Remember the dreaded black box under the hoods of so many cars that failed?  Well considering the fact that this was cutting edge technology should it come as a surprise that many of these new technologies were a little unreliable?  The same basic premise was also at work in the manufacturing of furnaces.

In the eighties most of the manufacturers were racing to develop high efficiency furnaces that integrated some form of electronically controlled ignition and onboard component control.  Not only that but new technologies were being invented in heat exchanger and venting design.  The furnace that Grandpa had was quickly becoming a thing of the past and so also for a time was its reliability.

Where is all this going?  My advice for homeowners that want to help lead a new technology revolution is to purchase all of the latest equipment coming down the assembly line.  This will help innovative companies patent and manufacture new energy saving designs.  My advice for homeowners that wish to have reliable equipment- wait a few years for the cutting edge stuff to get the bugs worked out.  Some of course will choose to be brave and we should applaud them.  Others will choose to be cautious and we should applaud them too.

Myth buster # 25

Written by Randy

What to check before you call a service company

Three basic items to check before calling for service.

1) Make sure power to the furnace is on. Usually there is a switch on the side or top of the furnace, hint: try turning the power off for one minute and then turn back on. Even furnaces have computers that need to be reset for various reasons

2) Check for proper thermostat setting. If the thermostat is in the heat position and set above room temperature try turning the heat/off/cool switch to off and then back on.

3) Check the manual gas valve located on the gas piping coming into the furnace. Make sure the valve handle is parallel with the gas pipe.

Taking a moment and checking these items I’ve mentioned may prevent a larger percentage of service calls.  However, lest we should overlook another basic maintenance item on the furnace checklist, make sure you have changed the filter in your furnace before calling a repair company.  Furnace companies will sometimes view a dirty filter as a reason to charge a customer even more.  Although this behavior is not very nice, or perhaps ethical, some technicians will consider a dirty filter as the homeowner’s lack of interest in saving money.  “Heck, if they don’t have the time to change a filter than they certainly won’t mind paying the bill for it.” 

On the positive side, if you follow these steps you may even solicit the opposite response from your heating and cooling company.  Just tell them that you tried performing these basic steps but found the problem was something more complicated then the average homeowner checklist. Whenever a customer has shown some interest in solving the problem before calling our company I always try to put myself in their shoes.  If they went to this trouble they are probably concerned about an expensive repair bill.  I have attempted a few automobile repairs on my own for this very reason. 

Hope this gets you back in operation and saves a few dollars!

Written by Randy