Frequently Asked Questions on an Hvac High Performance Quote

Here are some answers to some frequently asked questions regarding high performance HVAC Installation Price/Time Quotes:

 

What is the size of the HVAC replacement sytem that you are quoting?

The size being priced is for a 3 ton – however I do not really price
by the size – because I do not know what size you will need until I do
the calculations for the sizing. Therefore if we need a 4 ton or a 5
ton I do not raise the price, as long as that is what the calculations
are telling me. I have done enough of these on similar houses to know
that it will be close to a 3 ton for your house (simple double pane windows
with typical window surface areas, 2 story, with 2300 floor area, Las Vegas at 110 degrees out).
That price is for a 16 seer two stage unit with special settings on
the thermostat so that second stage does not engage unless the
temperature starts to go up if first stage does not cut it. When we
build systems like this they only cost near 1kw per hour to run. That
is about $0.14 per hour to run and this puts the cost at around $1-2
per day to keep the house cool at 78 degrees.

I was just looking over a system yesterday, we installed two years back, that was a 3 ton on a
3300 sq ft home and the second stage had never come on – was running
on about 2 tons, since we installed it.

 

Why are the ducts so expensive? R8 duct does not cost that much really.

On the ducts at your home – those are going to be a challenge –
because your attic does not have much room at all. The price for the
parts, including new plenums, start collars, 90 degree elbows, new
operable curved blade grills, etc gets up to around $1000 – 1400. Then
it takes two guys about 2 days normally to do the ducts and the
plenums – but with yours it will take an extra day for sure to figure
it out and navigate and get it installed (still no guarantee it can be
done – need to have my installer look at it and think about it first –
we can have him look at it for free if you are really interested.) We
do a lot more on a duct installation than a typical contractor,
including sealing every single joint with duct mastic prior to and
with assembly – This makes the duct leakage near zero – on the stuff
we can get access to. We use metal 90 elbows at all supply registers
and at returns if we can fit them. Each run is designed for the
airflow as called for by the sizing calculations and each run has an
air balancing damper for adjusting airflow to within a set parameter.
We oversize the return ducts – so that the duct pressures are within
tolerances set by the equipment manufacturers – this means the fan
runs at about 150-350 watts on high airflow instead of around 700
watts.

 

Why are we adding insulation, and what are we doing exactly?

The added insulation is for making insulation repairs as the attic
gets disturbed, and as well we will then cover the ducts that we can
in insulation – putting the average r value up to near R20 for just the ducts.

Most AC energy is lost in the ducts, as typical is 30% btuh is lost in the
duct work. We reduce this by using blow in insulation and building
dikes and working to get the ducts covered as much as possible. The
latest research from testing just done in the last year tends toward
most energy is lost in the return duct work – so figuring out how to
bury and cover this duct work is key.

Other than that we bring the attic insulation up to about r40 and this has been found to be a cost
effective improvement for homes, where you can get access to the
attic. Also we are already in there and this is a good time to get it done.

 

Why will your work take so much longer? Other AC contractors say they can do it in half the time.

 

Where most contractors would be able to go in and replace an Hvac
system appliance boxes in a long day (with little care in the world about
the bad duct problems). That is easy money for those contractors – but
the disservice is to the homeowners really. Here is what we find after
we install a system – we test it several ways and spend half a day or more just
making adjustments to optimize the system – commissioning. This is a
painstaking process and the last thing an installer wants to do is fix
a system that was just installed – but needing to fix it happens a
lot. We tell the systems to do things – and when we test we find they
aren’t doing what we thought they were supposed to be doing. You cant
know this until you test it. And we find that we make a lot more
mistakes than we think we do.

But with testing and commissioning we get them fixed up and become even better installers on the next job.

 

 

Buying an air conditioner: 8 smart strategies – Link Re Post

I found this blog post on a news alert. This has some good information.

Buying an air conditioner: 8 smart strategies

 

Here is a link to this posting.

A Great HVAC Work Scope

Efficient Air Conditioning  — Las Vegas — High Performance HVAC, High SEER AC Install, Energy Star Air Conditioning, AC Replacement, Work Scope:

  • Remove existing equipment.  Reclaim refrigerant, and disassemble and remove existing split system air conditioner. Recycle old equipment to metal scrap yards.
  • Install HVAC system in accordance with ENERGY STAR® Quality Installation Guidelines. See Bid Comparison Checklist.
  • Perform Man J calculations to right size the HVAC system per upgraded energy features of the home. Measure ceiling area, wall area, window area, lighting, people and other loads. Calculate amount of heating and cooling needed. Note 400 sq ft a ton is 30 year old technology and will result in systems being sized 2x too big – and this will waste a lot of energy, cause the system to turn on and off a lot, and result in hot and cold rooms.
  • Install new HVAC system. Install new line set if existing line set is not re-useable per its size or has dips in it where the oil cannot be removed. This oil will damage the new refrigerant. If there are hidden dips in the line set that cannot be accessed then the line set needs to be replaced, because the oil cannot be removed from these spots. All line set welding to be performed with nitrogen bleeding through line at time of welding – to prevent carbon build up that can and will damage refrigerant system. (Almost no typical technicians will weld with nitrogen bleeding at time of weld, even though they know that they are supposed to do this. If you ask them they will say that they do this – but when it comes down to it they do not do it. We have seen the highest priced AC Contractors, who can afford to do this – not do it – and make excuses as to why they do not do it.)
  • For the Desert, Air flow through new system to make at least 110% or more of manufacturer recommended flow. Special settings to put airflow at 480-580 CFM per ton of air conditioning in the desert. This is a setting for desert conditions where we want all energy spent on cooling the air and not on removing moisture from the air that is already very dry at 20% relative humidity typically in the home in the summer. Typical installed systems that we test are getting below 350 CFM a ton, and this is because most HVAC contractors do not pay attention to the amount of air going through the system. They just install the equipment and do not check to see that the equipment is doing what it is supposed to do. – This kind of checking after the equipment is installed is called commissioning. Comissioning is part of the Energy Star Quality Installation Guidelines.
  • Install new specially programmable thermostat compatible with two stage HVAC system in the same location as current thermostat. Special settings only allow first stage to run and second stage only if needed. Second stage will never run; only in rare cases and less than 1% of the time will second stage be needed. (There are only a couple of thermostats that can be gotten that can be customized to do this that I have found out of hundreds of thermostats – this setting is a big advantage in energy savings. Unless we are installing the system or you are a student of our classes please do not ask us which thermostats can do this – as we will not tell.)
  • System to not exceed manufactures allowable static pressure before and after the indoor blower fan of the system. This is almost never accomplished by typical HVAC Contractors, as they never test for this. 95% of existing systems we have tested fail this test. As a result, contractors who do not habitually test for this,  do not know of the failures and do not then plan to repair the duct and return duct problems that lead to this. The typical high pressures result in poor airflow and high fan watts consumed. This reduces the entire systems efficiency. If handled correctly the system can get efficiency performance that exceeds manufacturers listed capacity! – this is a fact that has been proven in an official case study that will soon be released by a professional third party who specializes in this kind of testing.
  • Optimize refrigerant levels. Use digital gauges that have been recently calibrated. Verify unit by super-heat AND sub-cool refrigerant charge levels  – not just one or the other. With calibrated tools and verifying both super-heat and sub-cool – vital errors do not get left on the system. These vital errors can cost easily 10% in additional energy costs or more.
  • Provide reporting to property owner of the above inspections and tests, and fixes and results. Provide copies of manufacturer warranties. This is good recordkeeping and copies should be left of this information for future use by technitions who need to study the current system before working on it.

Energy Fit Nevada and Earth Day

Efficient Air Conditioning is a proud member of HomeFree Nevada and participates in the Energy Fit Nevada program.

 

We are celebrating Earth Day with a toast to our new slogan: “Keep More Green in Your Pocket”.

Efficient Air in the first quarter of this year has completed at least 7 Energy Fit Nevada projects, with instant rebates for homeowners amounting to and beyond $12,000 off instantly. Instant rebates means that thee is no paperwork for the homeowner, and we discount the price of the work right off the top. That cash does not come out of the homeowners pocket.

Our average instant rebate on an AC replacement system is $2000. A lot of times we can get more instant rebates than that because of the availability of rebates from other programs coming from NV Energy and SW Gas.

“We were able to get one property owner of a 4 plex $7,000 in instant rebates when 4 systems were replace on the 4 plex. Some other work was being done there but the incentives amounted close to above 30% off the HVAC work done. That is a lot of benefit. Also those units are expected to save beyond 30% of the energy bills. He will have no problem keeping tenants in those units.” – Chris Cadwell, President of Efficient Air

 

 

 

Install a Direct Current Indoor Fan Motor

Installation of a DC motor in HVAC for Energy Efficiency does reduce watts and increase system SEER.

Do this as a retrofit option on an existing system.

Here are at least two of the motors out that we have installed:

Fieldpiece Concept 3 LER. You can see this motor for sale at Amazon. This motor is good for smaller HVAC units that are not packaged all in one units. It only comes in 1/2 hp. The airflow maxes out at 1400 cfm and you would not want to run it at that high of CFM. That makes this motor good for only a small range of systems for airflows up to 1200 cfm or so. The wiring is simple but does not wire in like a regular fan motor, so it will take a little skill with instructions and schematics. The motor speeds are basically controlled by the thermostat. For dry climates this motor has a built in extended run time relay that helps save on AC costs. It does also have a torque adjustment screw. This is nice because you can manually set the airflow with it – but be careful to install it where you can access the adjustment screw. Also the motor is not reversable – so if the blower wheel does not go the direction you need it to – then you would need to get a new blower wheel. A benefit to this motor is that if you want the fan only to run it will run at 50% speed, and this is nice for air circulation without burning up watts.

 

Emmerson EcoTech®. This motor is easy enough to find online or at local suppliers. This motor costs a little more. This motor has several different models. I has 3 sizes 1/2, 3/4, and 1 hp. You essentially would install the same horsepower that would be taken out of any existing unit. It also has options for 110v or 220v – so pay attention to what is needed before you buy. Having these options means that you will likely find a motor that can actually works for your installation. It does have 4 speed taps and wires in like a typical motor that comes out. It also has a reversing function if you need it to turn an opposite direction. The drawback to this motor is that if you want a slow speed just for the fan to run – you will have to pull out your inner genius and wire in some relays to get it to power on the slowest speed tap, when the thermostat is only telling the fan to run. It is not easy to figure this out, unless you have done it before.

Genteq EverGreen. This one is for sale at Amazon as well. We do not have experience with this motor yet. This motor looks good, and I believe I studied this motor out few years ago and has a wiring system similar to the Fieldpiece Concept 3, where the speeds are controlled by the thermostat.

[If anyone has experience with this motor or other DC motors please comment and contact me so that I can add to this post]

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One thing to be real careful about with these motors is the brackets that hold them in place. Some manufacturures of existing equipment like to use special mounts for motors. In a lot of cases you will need special retrofit mounts that are available. Fasco Belly Band is one and there are other mounts available at suppliers. In some cases even these mounts are not compatible with some blower units. There is nothing worse than going through the motions and then finding out that it cant be done in the end. In some cases you may not be able to find a bracket that works for some particular systems. 

Remember that just dropping in one of these motors does not guarantee that you will get energy savings.  Please review this post first: .. Cutting Fan Watts in Half.

 

 

 

 

 

HVAC and Occupant Health

“Never Do Harm” –  Hippocratic oath.

As HVAC professionals we are not health care professionals but may as well be.

Healthy Indoor AirWe are given the opportunity to make a positive effect on health by taking control of the living environment around the person. There really isn’t another trade that has as much control of this than HVAC installers and repair men.

~~~Really we should “do no harm” in building our shells and systems. That is at least a base expectancy. But our trade is one of the most dangerous as far as the harm that can be potentially done. Gas leaks, Carbon Monoxide, Duct leaks that pull in attic or crawl space air, potential for garage air and mold from water leaks – I have seen one of these or a combination of these on a lot of jobs I inspect. These problems often go un-noticed for years, and the health implications of long term exposure is not good. HVAC costs to repair are small in comparison to health care bills from long term exposure to some of this stuff, even if you are insured. ~~~

We do have opportunities to go the extra mile and make the indoor environment even more healthy than the typical. So our question becomes “How can we improve this persons environment in such a way that it improves their health?”

  • You will find that there are probably lots of ways to do this, but the easy stuff is just by controlling infiltration and ex-filtration, room pressures, combustion appliances and CO, and controlling where the fresh air comes from and how much of it they get. This is why being an energy expert is a must, and the Building Performance Institute certification at least gets a start on covering these things.
  • The next part is to make sure that the occupant can set the thermostat where they like it to be, and not have a heart attack when the bills come in. No seriously, we have done HVAC systems that only cost $35 a month to run at 75 degrees inside, in the super hot 110 degree outdoor Las Vegas summer time.

Just added the Online Efficient Air Learning Center

The learning center was added to this site, and the link was added to the menu.

http://www.learn.efficient-air-tech.com/

We are right now entering in some certification classes for BPI AC and Heat Pump Professional. We also hope to start an EPA refrigerants handling test prep course in the near horizon as well.

HVAC Savings Upgrades – Cutting Fan Watts In Half or More

There is a simple rule with regards to watts consumed by electric motors. Reduce torque demand and watt draw will reduce.

HVAC Motor SavingsElectric motor torque demand = watts cubed. If you can reduce the work demand of the motor, you can reduce the watts by a factor – to the power of 3.

That formula means that we can get dramatic results by making some improvements in the HVAC system. If the duct design is inadequate and the motor is working hard to get the air through the system – then fan watt draw will be higher than it needs to be. The solution is to reduce the amount of work the motor has to do to move the air.

One might say: “My system was installed correctly, therefore this is not really an opportunity to save energy.” That would be a wrong assumption probably 95% of the time.

Nearly all HVAC systems on residential and commercial installs fail the pressure test parameters – that the manufacturers require for the system to operate as intended. You guessed it – if you think you can just call up any AC contractor and have them replace the equipment and get 16 SEER out of it – that is incorrect. Unless it is installed according to manufacturers spec at least – you will never get 16 seer out of it. Just ask the AC contractor if they test the “static pressures” of the system and correct the ducts until it passes. (Warning: Dont just believe what they tell you – get an outside third party to verify the install – building departments do not check this stuff.) I commonly find 5 ton AC systems only getting 65% of the indoor air they are supposed to through the system. That means the fan is also working very hard to move that air, and fan watts are going to be high. As well the rest of the AC system is now suffering. This is because low airflow will reduce the systems capacity and Energy Efficiency Ratio by a factor of at least 65% if the airflow is 65% lower than it needs to be; at least a 65% reduction in efficiency because the fan watts will be high too!

If you can get more airflow than the required, and get it with low duct pressures – the Energy Efficiency Ratio of the whole system can be increased over what the manufacturer says is possible. Yes – that is right – we can exceed the manufacturers tested SEER and Energy Efficiency Ratio ratings – if installed very well — I have 3rd party studies on this from reputable measurement and verification consultants – well on the way. I will post how to get these kinds of results eventually when the study is officially released.

Here is a hint – a big part of the solution is listed below.

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The solution: Fix the duct problems. Then install a DC replacement fan motor (if the system doesn’t already have a DC fan motor).

Here are simple duct design tables based on successful residential installs. They show the area of filter needed and the sizes of return ducts needed. 90% of the duct design problems are in the return ducts to the system. These tables below are now published as part of the updated California Energy Code, and are now published in the book available on Amazon.com – Measured Home Performance: Guide to Best Practices for Home Energy Retrofits in California.

Click on the tables below to expand:

Return Filter Area Design

Return Duct Area

(We will cover installing a DC, or Variable Frequency Drive, motors in the very next blog post.)

HVAC Design – Technology To Save Energy

In homes that we can now repair the air leakage and insulation we can now get the building shell so good that we need much less than half of the AC and Heating power to keep them comfortable. This is good, because this is the entire reason we make these improvements.

The problem is that when replacing the heating and AC system for homes that have had shell improvments, manufacturers just do not make AC or Heating systems that are small enough.

The latest research is showing that design can be scaled back to much smaller and much simpler systems for a fraction of the cash compared to fancy way over-sized modulating multistage multi-zone systems.

Heater Sizing

Most heaters are too big for a home that only needs 18,000 Btu/h.

Steven Winter Associates – has documented case studies that support this type of design and that it works with occupant satisfaction.

One solution is to scale back design to “old school” and have a more centralized conditioning system. This would be a single source of air conditioning in the home with minimal to no distribution system. An example is a central heater in the hall, that does not nor did it ever have ducts to distribute the heat to the outer rooms of the home.

There is a modern twist on this however. Ductless mini-split Heat pump and Cooling systems are in wide use around the world. They have been around long enough and used in enough volume around the world to be a proven technology. These are centralized in design approach. The modern twist is to use very low cost exhaust ventilation fans to move conditioned air through the house. Theresults of this design approach are positive and tend to indicate this may be a plausible trend in energy saving design.

Ductless Minisplit savings for Las Vegas

Savings are based on actual results in actual energy savings on as built homes.

The above graph is based on two of the same home models with the same upgraded insulation. One home has regular over-sized heating system that we can typically get from regular suppliers and manufacturers. The regular system also has a typical duct system for air delivery. The other system is a ductless mini-split heat pump, with a tweak on the delivery system. Even though the energy saving system had two exhaust fans to move air through the house, it still cost way less to run – because the heating system was not over-sized, and the delivery system is much more minimal and simple.

Below are some plans and pictures of how to distribute the conditioned air for the centralized energy saver, and are part of the plans for the studied energy savings as in above.

Exhaust Fan Distribution

These fans are used to distribute central air.

Exhaust Fan Distribution Plan

Here is the sample plan for this distribution.

 

The fans and this plan were used in the study above. There was no setback or programmable thermostat needed for this system to get the energy savings as in above.

 

 

 

 

 

How well did the temperatures fare in the rooms? This was studied as well. The results were good. There was no more temperature varaiances than there would be in any typical home, 3-6 degrees from room to room.

Hot and Cold Rooms

The temperatures in each room were studied and the results were good.

I predict this type of simple centralized system with minimal distribution will become way more prevalent in the future, on homes with better insulation.

Here are the reasons: 1) The installation cost is very low 2) The installation is simple in nature and therefore average HVAC installers can do this with very little training. 3) The equipment costs are low 4) The energy savings is dramatic 4) The comfort performance is adequate 5) The maintenance requirements are simple 6) The equipment technology is proven and tested.

All in all I see it as the most affordable and feasible way to get dramatic energy savings coming up in the future horizon of prevalent AC installations. Of course it may take a decade or two before the American public accepts this type of install. Americans are just too used to ducted systems now – and may think something is wrong with this type of install and see it as not “typical.”

This is not to mention that there are a few systems out there that can be ducted with very simple means – eliminating the need for exhaust fan distribution – but the install on this type of ducted mini-split system is more complicated and would require an expert.

 

Leaky Air Conditioning Ducts in Las Vegas

This was a system that we tested with our “Duct Blaster,” a machine to test how tight or leaky ducts are.

Leaky AC in Las Vegas

Heat Pump with Back Up Electric Heat

We found this system was so leaky that we couldn’t even register it with our tools. The closest we could get was that it was over 50% leaky.

Those holes and boards below are direct to the crawl space

We started to take this system apart to see what to do to fix it. What we found was disgusting. It was pulling unfiltered air from the crawl space. What made matters worse is that the humidity that the system removed from the air, was dumped into the crawl space as well. Who knows what kinds of molds and other toxins this system was taking in for return air.

When you have platforms that are built to hold the AC system and also function as a return airway path, you have to get these things looked at and tested. These are often found in garages. Garage air is something that you dont want to breath into the house as well. There should be no way for air to naturally pass between a garage and a house, or a crawlspace and a house. And you for sure do not want moisture from a crawl space to enter a house, but it is usually one of the main ways unwanted moisture enters a dwelling.

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 The solution – take the system apart and re build the install the way it should have been done. Normally we dont have to go that far – but this one was so bad it needed it. The energy savings and instant rebates helped make this project one that will easily pay itself back in one year. We were able to capture $1660 in instant energy saving rebates on modification work on this house!

Starting to seal connection to crawl space, building metal duct for air to pass through.

We are fixing this problem for the homeowner. They are lucky that they found us and that we know what we are doing. This was their retirement home, and who knows what the long term health effects something like this would cause eventually.  We already have so many toxins in our environment – that lead to oxidation and a break down of our bodies.  In the Las Vegas dry climate, we get away with crawl spaces that are not retrofit for moisture protection just because it is so dry – but crawl spaces should still get a periodic inspection. Look at what could have happened above with the moisture being dumped into the crawl space, and pulled right back into the air stream with a few added contaminants.

The potential cost savings of the long term negative health effects from duct leaks probably way outweighs the energy savings by a long shot. We found and fixed these problems before the homeowners ever moved in. Lucky for them.

We fixed other problems with this install, like the electric heat strips being wired to come on every time the heat pump turns on. Those heat strips are only for back up. Probably this was some AC techs solution in the winter because the unit was taking in 20 degree crawl space air to condition and heat the house. I have seen winter utility bills go into the $500 range when they are wired like this. This one would have been a lot more than that!

 

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2-24-2012 — We completed this system and the total duct leakage went from over 50% to a final result of 9%. If we meausred leakage to outside it would probably be below 6% leakage which is Energy Star standard. The homeowner noted that the home no longer smelled “musty like and old home.”  — The smell improvement was an unexpected result – and would have been something that may have just been tolerated and gone along with having and old home, had we not made a big difference there.