CIBSE publishes several guides to HVAC design relevant to the UK market, and also the Republic of Ireland, Australia, New Zealand and Hong Kong. These guides include various recommended design criteria and standards, some of which are cited within the UK building regulations, and therefore form a legislative requirement for major building services works. The main guides are:
The next step was cleaning the cold air returns. He found a good spot to drill an 8” hole for his vacuum hose. The procedure matched the other air ducts except that when he finished at the two cold return registers he drilled several holes in the cold ducts in the basement and blasted air into them. Because of our houses age and the upgraded return system, I noticed that the main sheet metal return duct had no top but was just butted up against the ceiling in the basement. When he blasted air in, dust and crap shot out the edges along the ceiling. Once he finished that he removed the filter and “swept” out anything at the bottom of the return with his hand into the 8” hose.
EPA does not recommend that air ducts be cleaned except on an as-needed basis because of the continuing uncertainty about the benefits of duct cleaning under most circumstances. EPA does, however, recommend that if you have a fuel burning furnace, stove, or fireplace, they be inspected for proper functioning and serviced before each heating season to protect against carbon monoxide poisoning. Some research also suggests that cleaning dirty cooling coils, fans and heat exchangers can improve the efficiency of heating and cooling systems. However, little evidence exists to indicate that simply cleaning the duct system will increase your system's efficiency.
I am in need of HVAC ADVICE!! I need a new furnace badly, mine is cracked. I have bought both a 95 % AFUE furnace and a 5 Ton evap coil, I figured it should all be replaced at once for both cost and efficency. My question is with all the negaitive things I have heard about companies ripping you off, what type of price should I pay someone for putting in those two items and bringing everything in my attic up to code? I have been quoted $550 - $ 3300. Wide margin here!! Then of course comes the licencing part!! I know in my heart that I should use a licenced contractor but I have had such bad luck and prices from them that honestly one that was licened in Ga. and just not here in TN and is a tech. which charges 1100 - 2200 less sounds good as so long as I pay some type of Profenial HVAC person say $100 to inspect the work after its done and before I pay them.
A small number of products are currently registered by EPA specifically for use on the inside of bare sheet metal air ducts. A number of products are also registered for use as sanitizers on hard surfaces, which could include the interior of bare sheet metal ducts. While many such products may be used legally inside of unlined ducts if all label directions are followed, some of the directions on the label may be inappropriate for use in ducts. For example, if the directions indicate "rinse with water", the added moisture could stimulate mold growth.
An important component of natural ventilation is air change rate or air changes per hour: the hourly rate of ventilation divided by the volume of the space. For example, six air changes per hour means an amount of new air, equal to the volume of the space, is added every ten minutes. For human comfort, a minimum of four air changes per hour is typical, though warehouses might have only two. Too high of an air change rate may be uncomfortable, akin to a wind tunnel which have thousands of changes per hour. The highest air change rates are for crowded spaces, bars, night clubs, commercial kitchens at around 30 to 50 air changes per hour.[17]
Without proper ventilation, carbon monoxide can be lethal at concentrations of 1000 ppm (0.1%). However, at several hundred ppm, carbon monoxide exposure induces headaches, fatigue, nausea, and vomiting. Carbon monoxide binds with hemoglobin in the blood, forming carboxyhemoglobin, reducing the blood's ability to transport oxygen. The primary health concerns associated with carbon monoxide exposure are its cardiovascular and neurobehavioral effects. Carbon monoxide can cause atherosclerosis (the hardening of arteries) and can also trigger heart attacks. Neurologically, carbon monoxide exposure reduces hand to eye coordination, vigilance, and continuous performance. It can also affect time discrimination.[15]

Two weeks go by and no phone call from HVAC Service regarding install date, or any update at all.  I call them to check in to see if they have put me on the schedule and when I can expect to have the AC installed.    You can tell by the discussion I had with the lady on the phone that they completely forgot about me and have not scheduled anything.  She says she needs to get in contact with the owner because she has no idea on the availability of the crane.  I was told that she would call me back by the end of the day with an update.  Surprise, surprise, no phone call.  


I’m really not convinced that duct cleaning is of any value. My roommate wanted the ducts cleaned so he called some company. My scam senses is already tingling. They came in with a big negative pressure fan. Did some blowing and sucking in different vents. Then they tried to upsell a full system cleaning. They wanted to pull the blower and clean the heat transfer box at $700 per heater unit. I have a big house so we have two units. They also tried to sell us some “custom” $250.00 Air Lifetime air filters. At that point I pulled the BS get the hell out bell. After paying $520.00 for just the cleaning, I paid the bill and sent them on their way. I replaced the existing filter with the good old and cheap paper filters at $10.00 each. Duct cleaning… I’m not Impressed.
He proceeded to clean each heat register by removing the grille and blasting it with an air pressure hose toward the duct opening thinking that the dust would magically be sucked inside. In one room this caused a ceiling smoke detector to go off because the excess dust fooled it into thinking there was smoke. I put my hand in front of a register he wasn’t working on and could hardly feel a suction. Although we discussed how I open and close damper doors, I realized later that he never checked, opened or adjusted them during the cleaning. He could have closed all but the one he was working on in order to increase suction results. His next step was to blast air into the duct and then attach a “squid-like” device that slapped around inside the duct as far as he could reach. This is important! In a newer house, ducts have long straight runs from the furnace. In older houses like mine they can turn and twist. In fact, the duct we have a problem with runs straight up from the basement inside a wall and turns 90 degrees into a soffit for three feet then into two 90 degree turns to get into the floor joist area for another two feet and finally a 90 degree turn up to the second floor register. When he cleaned this one he could only get three feet into the register with the hose or squid because of the turns. That was the case with most. Hardly what could be described as a decent cleaning.
If you’re purchasing from a big-box store, you can expect to pay approximately $120-$1,000 for a window unit. Window units are appealing for their quick setup and relatively low cost, but they can use more energy over time than central air and only cool the room in which they’re installed. The price will vary depending on the type of air conditioner you buy and its cooling capacity. Window units, which require minimal installation, are one of the most affordable options on the market. Portable air conditioners don’t have the cooling power of a window unit, but they do have the perk of being transportable from room to room. Expect to pay between $225 and $800 for a portable air conditioner, on average. The cost of an air conditioning system with coils, condenser and line (not including installation or ductwork) can range from approximately $2,000 to $4,000 or more. If you don’t have (and don’t want to put in) ducts, a ductless mini-split air conditioner is a good option, although pricey up front. Pricing can range from $650 to $4,250 per unit on average; you’ll need one unit for each room in which you want temperature control.

Some Service Professionals are employees, franchisees, dealers, or independent contractors ("Corporate SP's") of larger national or corporate accounts ("Corporate Accounts"). In such event, you may be matched with the Corporate Account entity or with one of their Corporate SP's. The above screening criteria is not applicable to Corporate Accounts, and therefore, HomeAdvisor does not screen the Corporate Accounts or Corporate SP's.

Dehumidification (air drying) in an air conditioning system is provided by the evaporator. Since the evaporator operates at a temperature below the dew point, moisture in the air condenses on the evaporator coil tubes. This moisture is collected at the bottom of the evaporator in a pan and removed by piping to a central drain or onto the ground outside.
Heating, ventilation, and air conditioning (HVAC[1]) is the technology of indoor and vehicular environmental comfort. Its goal is to provide thermal comfort and acceptable indoor air quality. HVAC system design is a subdiscipline of mechanical engineering, based on the principles of thermodynamics, fluid mechanics and heat transfer. "Refrigeration" is sometimes added to the field's abbreviation, as HVAC&R or HVACR or "ventilation" is dropped, as in HACR (as in the designation of HACR-rated circuit breakers).
Pro HVAC company Southern Comfort Mechanical says on its blog, “If there’s mold growth inside the handler due to excess moisture, algae in the condenser drain line or a dirty evaporator coil, it can negatively impact your AC unit’s efficiency. The filters inside may also build up excess dirt and become clogged, which will also make your AC [or heat pump] waste energy trying to sustain the cool climate inside your home.” These issues are easy to solve. They don’t require replacing the air handler.
Fast forward 1 year and 1 week and the circuit board that HVAC Service had installed has failed again. They came out and said that it failed from water condensation dripping onto it, so we needed to replace it and reroute the pipes to prevent future water damage.  That would cost double what I paid last year.  Why didn't they fix the problem last year at the initial repair instead of putting in a circuit board that was bound to fail again?!? They were strongly recommending that the furnace be completely replace for a huge fee to avoid the same thing happening again.  I paid $59 for them to tell me they didn't fix it right last year. This didn't feel right, so I sought a second opinion.
Installation: The old furnace is disconnected from the ductwork plenum, exhaust flue, gas and electrical hookups. In most cases, a new plenum must be made onsite or ordered from a local sheet metal fabricator. A new vent might be required too. The furnace is set and reconnected. Adjustments to the blower fan speed and burner are made to optimize furnace performance for your home and climate.
If you believe that the AC's not working or you're getting little or no cold air, check these three things first. Make sure all the registers in the house are wide open. Then be sure the furnace filter is clean. Then go outside and clean off the condenser coils (Photo 2). If several registers were closed or the filter was clogged, the reduced airflow could have caused the evaporator coil to ice up and stop cooling your home. If you've changed the filter and opened all the registers and you're still not getting airflow at the registers, deice the A-coil. Move the thermostat mode switch from “Cooling” to “Off” and move the fan switch from “Auto” to “On.” Let the blower run for at least 30 minutes or until there's good airflow at the registers. Then turn the AC back on to test it. If it works for the next 12 hours, you've solved the problem.
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