Assessing Your Payback on a High Efficiency Equipment Purchase

HAVE LEGITIMATE EXPECTATIONS

In this era of ever rising energy costs which far outpace the inflation rate, many new customers have entered the HVAC marketplace looking for new equipment.  In an effort to gain those new customers attention many new claims are being made on a daily basis through all sorts of media regarding the effectiveness of a their said equipment.  Don't rely on advertising or unqualified opinions claiming fantastic amounts of energy savings.  Generally when an outrages number is quoted such as, "Save 50% on your heating bill this winter!," the statement is loaded and depends on several conditions being met.  For the vast majority of home owners a savings of 50% on your heating appliance is just not a reality.  Claims have also been made regarding the current condition of older equipment such as, "Replace that old 60% efficient furnace with a brand new model...," Let's face some undeniable facts here, for a gas fire appliance to actually run at 60% efficiency the flue (chimney) temperature would need to be between 800 F and 1000 F (varies based on excess air content of flue gas).  Those are staggeringly high numbers that the average furnace is probably incapable of putting out, unless there is a catastrophic failure going on.

We're not saying that drastic reduction in energy use can be realized but rather to not expect all of it from installing a new piece of equipment like for like.  Installing equipment that is 20% more efficient than the old equipment obviously will save said amount, but at a cost.  If energy, for most people money, savings is your goal the probably the most cost effective measure is to use less energy. 

USE LESS ENERGY!

 You may be saying to yourself, "Huh?? I thought that is what the point of this discussion was?"  It is, but we should define our terms a bit hear.  When discussing payback, we are trying to discover the amount of time it takes for a piece of equipment to pay for itself based on efficiency increase.  The efficiency of a system is the ratio of the energy out vs. the energy in.  A higher efficiency unit uses less energy in, thus has a higher efficiency.  On the top side of that ratio is energy out, which you also have control over.   This is what I would term, Energy Conservation, or using less energy.  In this category are some of the cheapest alternative to lowering your utility bill.  Such items as a Programmable Thermostat, adding insulation, isolating unused rooms, and using the sun more effectively.

In a related article please see the graph regarding the energy savings from changing the set point of the thermostat.  To really make a programmable thermostat effective the user needs to adjust set points as often and as much as possible.  The effects on energy usages are clearly shown on the three curves, and obviously you want to establish the most time you can with the greatest setback.  Obviously most people wouldn't be comfortable with a 50 F house in the winter, however most can sleep with a few blankets and at 60 F.

 CORRECTLY SELECT EQUIPMENT SIZE

 Having your heating or cooling equipment correctly sized for your application is often overlooked as a source of savings.  In this case, bigger is not always better.  If your house is older and you were not involved with the original equipment selection, then definitely do a calculation.  If your house is new, then definitely do a calculation.  First off its not that difficult, and actually kind of interesting.   Spending some of your own time evaluating your house construction not only allows for accurate data input, but gives you the chance to identify room for improvement in regards to insulation, vapor seals, etc.  DO NOT rely on the builder of your house decades ago who you probably don't know, nor have any reason to trust.  If hiring a contractor, if they don't do a detailed calculation, and then share and explain the results to you, move on and hire his/her competition who does.  Even if hiring someone else to do the calculations, we suggest you double check the data yourself.  This one decision can not only dictate the energy efficiency, but also very importantly the maintenance of the equipment. A very cost effective software solution is available for the home owner to do their own analysis by HVAC Computer Systems Ltd.

DO A COMPARATIVE ANALYSIS

This a wonderful website called HVAC OpCost.  Use it to not only get an estimate but compare operating costs.  Some things to consider while using this tool.

1. The sizing function is only an estimator, obviously a 1500 square foot house with a wall of windows facing south has a different load than a 1500 square foot house with few windows.

2. Use the tool to not only compare between your old system and a new system, but to also decide between incremental cost differences (i.e. 94.1 vs. 95.0%  efficiency)

3. Sometimes it takes a couple iterations to get your calculations right.  You may have to massage your square footage or existing equipment efficiency to get the utility bill to more closely reflect your actual bill (less taxes, fees, etc)

DON'T OVERPAY FOR TECHNOLOGY

Finally, using your comparative analysis above and other information you have learned one more thing to consider is to not buy the Newest thing out there.  You tend to pay a premium for new technology, with little payback.  Manufacturers have to recover R&D costs and many people are willing to pay that premium, so the latest item is generally overpriced for its value.  You've probably seen this in the technology sector such as Cell Phones or computers, the newest item is generally hot for a few months then comes back to the pack as soon as a newer item is introduced.

© 2005-2008 ~ www.HVAC-Direct.com by G&H Engineered Systems.