Articles for September 2016

HVAC System- Repair or replace- The facts

Every Houston HVAC system requires maintenance or replacement at some point of time. But how do you know that it is time for either repair or replacement? Have you considered all the factors before calling your known Houston HVAC contractor for that repair or your nearest Houston HVAC company for installing new system?

You may be thinking that age of the HVAC system is the only criteria for choosing repair or replacement. Lifespan of 15-20 years? Is that what you have heard? Yes, you may have heard it right because US Dept. of Energy does say that the average life span of air conditioner is 15-20 years. But have you considered the fact that 10 years is the warranty provided by your system manufacturer through your nearby Houston HVAC contractor? Once that warranty period expires, you would be left without any coverage at a time when the air conditioner is most likely to break down.

Although you might not be facing any trouble with the functioning of air conditioners, there is always a degradation of performance with the passage of time. This means that the same air conditioner would use higher energy to provide the same comfort levels as time passes by. Not convinced? Why don’t you go ahead and check your utility bills? After 10 years, it might be worthwhile to actually replace your HVAC system and this can result in saving up to 40% on your utility bills.

One of the factors worth considering while deciding on whether the air conditioning unit should be repaired or replaced is the return on investment. If you are planning to move to a bigger house or change your locality within 3 years, it might be worth to actually repair the system rather than replace the system because if you happen to purchase a new one, you might just not be able to get your investment back.

So you must now be wondering as to when the system should actually be replaced. You definitely want to replace the system before any breakdown occurs. And when do breakdowns occur? Summers. That’s when the air conditioners are working the hardest. Planning ahead of summers is necessary so as to avoid a decision in haste to replace the system. If you sell the old system in haste, you might just not get a good worth for the system.

So to sum up the factors that are worth your consideration are system age, price of selling the old unit and purchasing a new unit, repair and maintenance costs, thermal comfort, warranty period and time left on your home and return on investment and last but not least safety.

HVAC System Basics

It’s hot, it’s humid. You turn on your Houston HVAC system and it provides instant relief. But have you ever wondered these machines operate. Houston HVAC Contractors might have informed you couple of times on how to maintain your HVAC system but never the basics. There are two types of refrigeration cycles: vapor absorption cycle and vapor compression cycle. Almost all of your home HVAC systems operate on vapor compression cycle. And therefore here is a lowdown on what happens in vapor compression cycle.

The first rule of physics is that the heat of vaporization is powerful: a lot of heat is required to convert a liquid into a gas and this is called evaporation in HVAC terminology and is similar to boiling. The reverse is also true i.e. a lot of heat is released while converting a gas into a liquid and this is known as condensation. So if the working fluid called the refrigerant is being evaporated, it means that heat is being absorbed by the refrigerant. And if refrigerant is being condensed, it means that heat is being released by the refrigerant.

The second rule of physics is that the boiling point of a fluid is a function of both temperature and pressure. The consequence of this rule is that a low pressure would induce boiling and high pressure induces condensation. So if you go to a city at higher altitude for example Denver, the water would boil at 195° F instead of normal 212° F. This is because at higher altitude the air is thinner and low pressure region exists. For the reverse, you may look no farther than your pressure cooker where the water would boil at a temperature of 230° F due to the high pressure environment within the pressure cooker.

Combine the above two laws and you have vapour compression cycle. A simple example is your spray aerosol can operation. When you spray it, your hands feel cool. This is because the by pressing the nozzle, some of the pressure inside the pressurized can is released and the liquid within the pressurized can is being converted to gas by decrease in pressure. The heat required for this process to happen is being given by our hand and thus our hands feel cooler.

So if the refrigerant is circulated in a loop, boiling can be induced by reducing the refrigerant’s pressure by passing it through an expansion valve. The refrigerant which is in a pressurized liquid state on the right of expansion valve turns to gas by absorbing heat from the inside of our rooms. The air is circulated over the pipe carrying the refrigerant with the help of fans. Similarly condensation can be induced by increasing the refrigerant’s pressure by passing it through a compressor. The refrigerant turns from a low pressure gas to pressurized liquid and thus giving out heat in the process.

As in the process of aerosol can, you spend energy to press the nozzle, the compressor here utilizes electrical energy to compress the refrigerant. The two fans also consume electricity for operation.

And that is it folks. It’s that simple and you now can visualize the air conditioning process.