Category: Geek

How to Improve an Electric Clothes Dryer (phase 1)

Electric clothes dryers are very simple devices which have not changed much in 50 years. While electricity is very efficient at generating heat (virtually 100% conversion from electricity to heat), it is not terribly economical. While there are now (as of 2024) heat pump based dryers, they are still fairly expensive (and I started this project almost 10 years ago anyway). I have undertaken to improve the economy of the basic, very reliable, electric clothes dryer.

My clothes dryer is a White Westinghouse Electric 27″ drum unit from 1988 or so, about 36 years old. I have had to repair / replace the main bearing, the idler pulley, the belt, and the front slides (multiple times). None of those repairs are terribly difficult once you get the hang of it. It was while replacing the idler pulley and belt that I was inspired to do this first upgrade (which I am calling phase 1). I noticed that the dryer pulled air from various places all close to the ground. My dryer lives in the basement and the floor in the basement is not the cleanest place (raw concrete on dirt).

Phase 1: Improved Airflow

I decided to pull the air for the dryer from higher up, filter the air, and push it so that the air came in the way I wanted.1 I also decided to add helper fans to the exhaust. In my installation, the dryer vent runs straight up for about 5 feet and then makes a 90 degree turn to the right before heading another 5 feet across to the window and outside. I theorized that if I could increase the airflow through the dryer, it would remove moisture at a faster rate and would dry clothes faster, requiring the high current heating element to run for less time.

I went about closing off all the various slots and holes that the air came into the dryer cabinet through. I fashioned a replacement vent panel (where the majority of the air came in) that connected to a 6″ duct pipe. I used a pair of 6″ vent pipe “helper” fans in series to force the air in after sucking it through a HEPA filter element I had lying around.

Bottom rear of the dryer (it is laying on it’s front) showing intake (left) and exhaust (center) ducting, as well as foil tape covering random opening (right).

On the exhaust side I ran 4″ duct up from the dryer exhaust connection (matching the exhaust connection size) as a I wanted to maintain the air velocity up the vertical segment so keep the lint flowing. Once I made the 90 degree bend to horizontal I increased the duct diameter to 6″ for the horizontal run. This causes a drop in velocity at that transition and any lint that is going to fall out of the air stream does so there, where it does not block the flow of air. Right before the duct leaves the house there are another pair (in series) of 6″ duct helper fans. I placed them here to keep them as far from the heat as possible. Neither fan has failed in about 10 years of use.

The exhaust (top) and intake (middle) before installing the HEPA filter over the intake.

The above was all relatively easy as it was simple mechanical work. The hard part was to come, automatically running the external helper fans when needed. My first iteration just had them on a separate power cord that we plugged in before we used the dryer. I did not like this as there was the possibility of running the dryer without the helper fans, in which case those fans would put more load on the dryer blower and slow the flow of air, the opposite of what I wanted.


The dryer ran off of 240 volts and the helper fans needed 120 volts.2 So I needed to find a source of 120 volts and switched so that they only ran when needed. I decided that having them running whenever the internal motor that rotated the drum and ran the internal blower was running was the best option.

Looking at the above wiring diagram it became clear that the only thing that ran off of 240 volts was the heating element. I also wanted the power for the external helper fans to be party isolated from the internal circuits. I pulled power from WHITE and TAN (C and X on the timer switch) to run the coil of a relay that then switched the power to the external helper fans. The additional load the relay coil puts on the timer switch contacts is minimal.

The last change to the wiring (which I just did while putting phase 2 into place) was to have that power for the external helper fas come out on a duplex outlet on the back of the dryer and have the fans wired with normal NEMA 5-15 plugs. I know this is probably not strictly to code (using the NEMA outlet and plugs for a very specific purpose, but it is safe and makes it easy to separate the ducting from the dryer for maintenance).


The automatic setting on the dryer has marks for less dry and more dry with 3 tick marks between them and 3 tick marks below less dry (more dry is at the very top). Prior to adding the external helper fans we needed to run the dryer almost all the way to more dry to have our clothes come out dry. After adding the external helper fans we could run the dryer one tick mark above less dry and the clothes were the same dryness (and much more lint in the lint filter).


  1. I learned about airflow management when I was a Broadcast Engineer. Most transmitters at the time had a blower that moved air through the transmitter and out a duct port. That duct port was typically vented to outside the building (often with a helper fan). The problem with this arrangement is that it lead to a net negative pressure inside the building, so air would come in through any gap or crack bringing with it any dust or dirt it picked up along the way. By configuring a blower to bring outside air into the building (via a filter to remove the dust and dirt) we then had the building at a slight positive pressure and that prevented dust and dirt from entering along any cracks or gaps. I later used this experience in computer server room and data center design. Bring air in and clean it on the way, keep the room at a slight positive pressure and you improve the air quality. ↩︎
  2. OK, I could have connected the helper fans in series and run them off of 240 volts, but I did not want a failure of one fan to stop the other, that is the other reason for 2, in series in terms of airflow and in parallel electrically, redundancy. ↩︎

What Does PK1048 Mean

Geeks love inside jokes. Most (if not all) Unix commands actually have a meaning and are not just an assortment of random letters. So why did I choose PK1048 for my domain and blog? Well, back in the earlier days of the Internet (I do not claim to have been around for the real early days of the Internet in the 1960’s and 1970’s) you needed a way to manage domain names. These are the names we use to refer to things on the Internet, like, since all the Internet knows is the numeric address of the systems. The Domain Name System (DNS) maps names to numbers (and other useful information) as well as numbers to names. In the mid-1990’s there was one entity tasked with managing all the domains for the .com and .org Top Level Domains (TLDs). That entity was Network Solutions. If you registered a domain you needed to configure and run DNS servers for it. You also had to let Network Solutions know the numeric address(es) for your DNS servers. To manage that information you needed a unique ID at Network Solutions. That ID was called your NIC-handle and my NIC-handle was pk1048 (because I was the 1,048th person to register a NIC-handle with the initials “pk”).

So “pk1048” was my NIC-handle and permitted me to manage domain registration records and DNS server records for a bunch of domains in the late 1990’s. I still manage registrations and DNS servers, but with many registrars and countless TLDs you don’t have a single NIC-handle you authenticate with anymore.

Who am I

When meeting someone new, an introduction is in order, so here is my introduction.

I am a “Geek” and I mean that in the sense that I seek to understand how everything works. Not just what buttons to push, but what the buttons do and why I might want to push them.

I went to a major technical institute in the early 1980’s and failed out after 2.5 years as a Physics major. I then leveraged my experience at the school’s student run radio station into a string of jobs in Broadcasting on the engineering side of the house. UHF TV stations on channels 67 (1.5 years) and 62 (6 weeks) and then 7 years at a VHF TV on channel 6. During this time I worked on everything from video cameras, audio equipment, video tape machines (2″ quadraplex, 1″ SMPTE C, 3/4″ U-matic, and even Hi-8), RF transmitters and receivers (55,000 watt UHF and VHF, 2 watt microwave, among others), and anything else that might break. I then spent 6 months as Chief Engineer at a small AM/FM (50,000 watt clear channel AM, not the company, but the class of AM station) fixing everything and even doing a full asset inventory and valuation (for the bankruptcy court, a long and different story). At about this point I finished the Associates Degree I had been working on at the local community college in Math & Natural Science, with a 4.0 GPA. I then spent about 2 years doing Sound professionally; systems design and installation, repair and maintenance, loading shows in and out, mixing, just about everything in the realm of sound.

It was at this point that my career changed directions from audio / video / RF systems to computers. I worked for 6 months part time as a Technical Writer editing class materials for a Unix Administration Class. That led to a full time job offer and I started down the path of IT in 1995. I have worked at or with three different “High Tech Startups” since then, typically on the systems management side, but I have also spent time doing web and other application development as well as managing a storage system of 250 TB (back when that was a lot of data) for a group of 800 lawyers.

Today I am no longer an independent IT Consultant, but a full time employee of the third high tech startup I was involved with. We aren’t really a startup anymore, but we are transitioning from being a small group of people working together to a small company working together. I mention all of the above so you know the diverse technical background I hail from.