Category: Rooftop Units

Q: “I need to replace this RTU but there is no data tag (or it’s not legible). How do I know what size unit I need?” With no data...... Read More

At cfm we are often asked: “How much outside air can we bring in thru a standard RTU?” The short answer is you can bring in as much as...... Read More

For this solution to be successful, you will need to REDUCE the system airflow in addition to installing the Rawal valve.  Lowering system airflow does TWO things: It lowers...... Read More

One of the most common reasons for rooftop service calls is incorrect airflow.  Low airflow will often lead to frozen evaporator coils, low pressure trips, sweating ductwork and low...... Read More

We get asked this question often. And for good reason, DOAS equipment is expensive.  If a building owner needs makeup air, in most cases a DOAS will be required....... Read More

Did you know: hot gas reheat operation (for dehumidification) provides NO benefit on a summer design day? This can be an easy mistake to make. (to clarify from the start, this is NOT...... Read More

Humidity, the 8th wonder of the world, is a tough nut to crack. Unlike sensible heat transfer, it’s very difficult to measure its movement into buildings through cracks, doorways, and other openings.But,...... Read More

Are rooftops a commodity?Maybe.But there is a lot to think about when replacing an existing unit, or doing a design/build job.Is quick and easy access important? Maybe we should...... Read More

EER, IEER, SEER, IPLV, HSPF… You have probably seen all of these terms before and never even thought of what the heck they stand for, or why you would...... Read More

Airside economizers are very simple in theory. Their function is to shut off the unit’s compressors and provide “free cooling” when the temperature outside is cold. Done, end of...... Read More