Your roof acts the same way.  It can easily reach 150º or hotter on a sunny day.  This heat will then be re-radiated through the attic and will be absorbed by your attic insulation causing high energy bills and comfort issues.

This video illustrates how a radiant barrier works – plain and simple.  Rather than absorbing the radiant heat from the roof, let’s bounce it back and keep the attic insulation cooler. If you keep the insulation cooler, then less heat enters the home and you save money and stay more comfortable.

Think of it this way:  Radiant barrier is your 1st line of defense against radiant heat and your attic insulation is your 2nd line of defense against conductive heat.  They will actually work TOGETHER for maximum efficiency and comfort.

Click here to view the embedded video.

Looking for more videos on this topic? Check out my posts below.

Adding more insulation space between the roof deck and the sheetrock can be expensive, labor intensive and will reduce the ceiling height in the new room.

One option is to ventilate the roof deck and install a radiant barrier BEFORE you install insulation and sheetrock. This method helps keep the heat absorbed by the roof AWAY from the insulation by creating a THERMAL BREAK to reduce heat flow by conduction. This method also forces the energy absorbed by the roof to be converted into radiant energy. Radiant energy then can easily be reflected away with a radiant barrier.

Think of this method as a ONE-TWO Punch against heat gain. The radiant barrier is the 1st line of defense against radiant heat gain and regular type “R-Value” insulation is the 2nd layer of defense. This video shows a fast and effective way to install a radiant barrier into your roof assembly to maximize comfort and efficiency for your new attic room.

Click here to view the embedded video.

Looking for more videos on this topic? Check out my posts below.

External unit of a ductless mini-split

Sometimes you can do all this plus more and STILL have comfort issues.  It may never get comfortable or it’s freezing one minute and then too hot a few minutes later.

If you have given up and are ready to throw in the towel, then take another approach. You may  benefit from a Ductless Mini-Split Air Conditioner.  What’s a Mini-Split?  The best description is a  window air conditioner WITHOUT the window. If you have ever traveled to the Caribbean or the Orient you see them EVERWHERE.  The most common brands are Mitsubishi Mr. Slim, Sanyo, Daikin, LG, and Fujitsu just to name a few.

Ductwork is a very western idea. By using a ductless mini-split, you can easily bring more air conditioning (heat removal) to either an interior space or an exterior room without a noisy window unit.

Diagram of how a mini-split ductless system works

An air conditioner basically has three parts: 1) Compressor 2) Fan 3) Coil. A window air conditioning unit has all three together.  In a ductless air conditioner, the compressor is OUTSIDE and the fan and coil are INSIDE usually connected by a ¼” or 3/8” copper tubing.  The beauty it that the inside unit can be as far as 100 feet from the outside condenser.

Installation is pretty simple since there is usually NO electrical requirements for the inside fan coil.  Power to the inside unit is brought from the outside unit along with the refrigerant lines.  This means that basically you can drill a hole in a wall, run a 3” bundle of copper tubing, hang the indoor air handler on the wall, connect condensation tubing, set the outdoor unit, connect power and just like magic supply additional cooling and heating to any problem area.

Inverter vs. Non-Inverter Units

WARNING:  Mini-split air conditioners all look very similar but operate very differently. Traditional air conditioner units act like light switches – they are EITHER ON OR OFF.  They turn on, run for a while and turn off.  A mini-split with inverter technology acts like a DIMMER switch that automatically adjusts based on the required “load”.

Indoor portion of a ductless mini-split system

Inverter air conditioner units have several advantages.  First of all being comfort.  You will not have a big “swing” between feeling too cool and too hot.  Second is dehumidification.  By running longer at a lower level the inverter will pull more moisture out of the air resulting in better air quality and a “crisp” feel to the air.  Another advantage is energy efficiency.  Inverter air conditioners operate at a lower amperage and do not cause spikes in demand charge or light flicker when starting up.  Finally, the best feature of installing a mini-split air conditioner is CONTROL.  Whether it’s a bedroom, office or media room, you will be able to keep it cool and comfortable without having to cool the entire house.

Mini-split air conditioners are the fastest growing segment in the air conditioning industry.  Ease of install, efficiency, improved comfort and better dehumidification are just a few reasons never to throw in the towel on keeping comfortable.

Window with solar screen installed

One of the most frustrating problems is having comfort issues with a particular room in your home.  These are rooms that you can NEVER get quite cool enough no matter how hard you try.  The usual suspects are: Rooms over garages, bonus rooms, media rooms, master bedrooms that “stick out” from the house, and home offices.  In this article, I offer tips to help fix these problem rooms.

In order to fix the problem, you must first ask, “What exactly IS the problem”?

The easiest way to view any room is simply to look at it as a big box.  Heat enters the box and the air conditioner pulls the heat out.  The problem occurs when you combine several rooms (boxes) on ONE air conditioning system.  The airflow to each room will dictate how fast each room cools off.  The problem is that the sun, exposure, windows and internal heat loads (lights, people, computers, etc.) are DIFFERENT for each room and can CHANGE throughout the day. The “problem” rooms usually gain heat faster than the other rooms on the same air conditioning system.

Properly installed radiant barrier foil

There are two methods to TRY to fix this:  1) Keep the heat from entering in the first place or 2) Pull MORE heat out.

1) Keep the heat out – We want to STOP heat from entering so we don’t have to deal with it in the first place.  Start with the windows. If a window catches direct sun you need to shade the window.  Solar screens, window film, awnings or natural shade (trees) will all help – take your pick.  Then focus on the thermal envelope.  Walls should be well insulated and have some form of sheathing (usually ¾” foam board) on the ATTIC side of any walls to fully encapsulate the studs and the batts of insulation between them.  We call walls that face an attic “hot walls” for a reason.

Radiant barrier foil should be applied above and around any problem rooms. Ceilings should be sealed airtight and have plenty of insulation and ductwork should be checked for leaks or constrictions.

Open chaseway showing missing "blocking"

Finally, if the room is on the second floor, look for what is called an “open chaseway.”  This is the area between floors that usually has electrical, plumbing or ducts running through them.  Older homes often are missing “blocking” and allow hot or cold attic air to slide BETWEEN the floors and cook or chill the room from the bottom.  Open chaseways needs to be sealed up.

2) Pull MORE heat out – If you have done everything to keep the heat out and you still can’t stay comfortable, then the only other option is to pull more heat out. This usually requires the expertise of a good air conditioning contractor. You could need larger ducts, more ducts, additional return vents or a combination of these.

Unfortunately, on many “problem” rooms these measures have limited success. In fact, you can do EVERYTHING and STILL have comfort issues in some rooms.  What do you do?

Look for part 2 of this article: When all else fails – how to keep ANY room comfortable.

Basically it works this way.  Radiant heat is heat that is transferred across either an air space or a vacuum.  This is how the heat from the sun reaches the earth.  Radiant heat acts similar to a sound wave.  By definition, you MUST have either an air space or a void for radiant heat to even exist.

If you don’t have an air space then you basically have a solid.  Heat can essentially only move through a solid by conduction. This is by direct contact.  This is how an egg cooks on a hot skillet.

So, without an air space, you cannot have radiant heat. Without radiant heat there is no way to have a “Radiant Barrier”.  In fact, because of the conductive nature of pure aluminum, if you install radiant barrier foil WITHOUT the required air space it will actually work AGAINST you and INCREASE Heat flow.

The bottom line is you MUST have an air space on one side of a radiant barrier for it to work.

Click here to view the embedded video.

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I put together a video to help illustrate how traditional attic insulation and radiant barrier WORK TOGETHER to make a home more comfortable and energy efficient.

Remember, traditional attic insulation – fiberglass or cellulose help to reduce Conductive Heat Loss.  A radiant barrier will help to reduce Radiant Heat Loss.  In cold weather, heat is lost in BOTH ways.

Combining good attic insulation and radiant barrier will give your home the best defense to stay warm in the Winter and cool in the Summer.

Click here to view the embedded video.

I've written several other posts on this that you might be interested in. Check these posts below:

Paint applied as a Radiant Barrier

You may have recently heard some Radio/TV ads talking about an “Amazing Radiant Barrier Paint that is applied to the underside of your roof”. And how it “reflects” over 75% of the heat to keep your attic cooler and save you money on your utility bills.

Let’s get some facts straight. There is NO such thing as RADIANT BARRIER PAINT.

The term “Radiant Barrier” is supposed to describe products that “Reflect” over 90% of radiant energy (think light colored and/or shiny surfaces like aluminum, silver and gold) or have an emissivity of less than .10. This means they can only “Release” less than 10% of energy as radiant heat (think a potato wrapped with foil to keep heat from being released).

The term “Radiant Barrier” has been hijacked by the paint installers to try to confuse consumers into thinking they are the same. This is like hamburger calling itself a prime steak.

Paints like Sherwin Williams E-Barrier, STS Coatings HeatBloc or Solec LO/MIT are NOT the same as radiant barrier foil.  I’m surprised the FTC has not stopped this fraudulent advertising or a lawyer has not created a class-action suit on the behalf of customers who thought they were being sold a “radiant barrier” by installers.

Paint products technically have their own name.  They are called Interior Radiation Control Coatings or IRCC’s for short. This is not as cool as being called a “Radiant Barrier”. Ironically, most paints don’t even qualify to be an IRCC since the definition of an IRCC is a product that reflects at least 75% or emits less than 25% of radiant heat.  Here are some test results of radiant barrier paints.

Paints will NEVER perform as well as foil radiant barrier products. Foil always reflects 97% of radiant heat energy.  This is an indisputable fact.  Radiant Barrier Foil is always superior to IRCC’s. Paints run into other challenges.  Because radiant barrier paints are “applied” rather than “installed” you get inherent variables in the application process.

First, how can you tell without testing if the product was put on too thick or too thin?  What about painting unprimed wood with paint?  Common sense says it will be absorbed by the wood and reduce the “smoothness” required for a good low emissivity surface. You will also need to paint the deck AND the rafters to get the maximum benefit.

Finally, what about cheating?  These radiant barrier paints are really EXPENSIVE, like $50 per gallon.  I’ve seen guys use cheap silver paint, or mix water with the good paint to extend coverage and reduce costs, which will also reduce the effectiveness of radiant barrier paints.  I’m sure there are many honest installers, but watch out for the bad apples.

The reality is that most radiant barrier paint products end up reducing radiant heat into the attic by about 20-40%.  This is far below the claimed rates of 75%.

There are claims that foil is not effective unless you get the whole roof. This is NOT true.  Any product, whether it be foil or paint has a cumulative effect, the more coverage the better.  A tree over part of your home still helps, right?

If you compare the math, you could actually put foil (reflecting 97%) over half the home and get more heat reduction than applying paint (reflects 20%-40% in real installations) over the whole home.

Don’t believe anyone that says that radiant barrier paint is as good or as effective as radiant barrier foil.  And remember, there is technically NO such thing as radiant barrier paint.

The short answer is NO damage will occur. Tests have shown that installing a radiant barrier in attics generally only cause the roof and shingles to increase about 2° – 5° Fahrenheit.

This may seem unbelievable since radiant barriers are sold on the fact that they will reflect 97% of radiant energy away from their surface. The question is asked “Where Does The Heat Go?” It is assumed that since the heat is reflected back towards the roof then the roof must experience a significant increase in temperature.

Let me explain exactly what is happening between the sun, the roof (shingles & decking material), and the attic.

First, radiant energy from the sun heats up the shingles. The actual temperature of the shingles is primarily determined by two things: 1) Shingle color – darker shingles absorb more heat and get hotter, and 2) outside air temperature. Obviously, your roof will get hotter on a hot-sunny day compared to a cold-sunny day.

Once the heat is absorbed by the shingles, it is transferred via conductive heat flow to the roof deck. The roof then becomes a “sponge” to hold the heat. On the other hand, air has a cooling effect. How much is determined by the actual outside air temperature and the amount of airflow on the roof either by wind above the roof or attic ventilation below the roof.

These factors: Amount or Angle of the Sun, Shingle Color, Outside Air Temperature, and Airflow will determine the “Maximum Roof Temperature”. At this point, the roof will not get any hotter. Your geographic location will also affect this. A roof in Las Vegas will get hotter than a roof in Kansas. In general, maximum roof temperatures will range from 130° up to 180°.

I mentioned that the roof becomes a heat “sponge”. As the temperature goes up it will want to release the heat by converting it to radiant energy. This radiant energy is emitted in all directions, both upward to the sky and downward into the attic.

By installing a radiant barrier, the energy heading towards the home will be reflected back up towards the roof and cause MORE heat to be sent towards the sky away from the home. This is similar to a light bulb with a reflector behind it. The amount of heat and light given off by the bulb is constant, but you would feel less heat behind the reflector and the light is directed to one side.

Shingle manufacturers also provide a full warranty on products installed over radiant barriers. Your geographic location and color of shingles are the two biggest factors in determining roof temperatures.
The bottom line is that shingles usually see a SMALL increase in temperature (usually 2°-5°) over radiant barriers. These results are from tests performed by the Department Of Energy. Plus, many tests performed by customers and installers support this fact. This slight increase in roof temperature is considered nominal and will have virtually no impact on the performance or life expectancy of your roof. Rest assured, Your shingles will NOT BAKE.

I’m about to reveal the FOUR SILVER BULLETS for making your home more energy efficient in HOT CLIMATES. I’m especially talking about your typical one-story, ranch style home in the South.

Picture yourself sitting in your living room on hot August afternoon. The sun is beating down and it’s about 95º outside. What’s between you and the bazillion degree sun?
Four layers: 1) Roof 2) Attic 3) Leaking Ductwork in the Attic 4) Insulation
If you fix each “layer” between you and the heat from the sun, your home WILL BE MORE EFFICIENT AND COMFORTABLE EVERY TIME!!! Guaranteed. It is not complicated; just follow the recipe for success.

Radiant Barrier Installation

Layer #1 – Roof
Problem: It gets to be about 150º or more and basically acts like a big sponge to absorb heat. This heat is then radiated to the next layer.

Silver Bullet #1 = Radiant Barrier
Installing a radiant barrier is the next best thing to a giant tree instantly landing over your home. Your roof will still absorb the heat, but now rather than that heat being transferred to the home, it will be reflected AWAY.

Layer #2 – Attic

Blocked soffit vent blocks attic ventilation

Problem: Because most attics don’t have enough (or proper) ventilation, the AIR inside the attic basically gets “Clogged” like a drain in a bathtub. The air has nowhere to go and it just heats up and “fills up” the attic. Hot air in the attic will heat up the insulation AND heat up your ductwork that is supposed to have nice cold air running through it.

Silver Bullet #2 = Attic Ventilation
Attic ventilation is real simple. All you need is holes in the top and holes in the bottom. The more holes, the more outside (relatively cool) air moves through the attic and the cooler the attic air. The lowest the air inside the attic can go is near ambient (outside) temperature. The overlooked key to fixing attic ventilation is usually more soffit vents.

Leaking ducts in the attic

Layer #3 – Leaking Ductwork In The Attic
Problem: Putting Ductwork in the attic is about a dumb as making ice cream in the oven. Since you can’t move the ductwork, at least keep it from leaking. Most homes have duct leakage ranging from 15-50%. Older homes and homes with old metal ductwork usually have the highest leakage. What this means is that probably 25% or more of the cold air you are buying is being blown into the attic OR Hot dirty attic air is being SUCKED into your home if the leaks are on the return side of the AC system.

Silver Bullet #3 = Seal Ducts In Attic
If 30% of your water from your sprinkler were spraying into the street, you would fix it today. Why not do the same for your ductwork? Have your ductwork sealed or replaced. A tight duct system will save energy and increase comfort. Plus, indoor air quality will improve by reducing humidity and dust from being pulled into the home.

Attic Insulation being blown in

Layer #4 – Attic Insulation
Problem: Most homes do not have enough attic insulation to create a good thermal barrier between either the heat in the summer and the cold in the winter.

Silver Bullet #4 = Attic Insulation
Increase your attic insulation to the recommend level for your area. Check the DOE (Department Of Energy) for recommendations.

There you go. Four silver bullets for fixing your summer electric bill. Your attic is waiting.

I've written several other posts on this that you might be interested in. Check these posts below:

Click here to view the embedded video.

Looking for more videos on this topic? Check out my posts below.