Thermal cyclers have become much more affordable over time. The author's first lab paid over $10,000 for a basic thermal cycler, whereas now quality machines can be found for under $5,000. An interlaboratory study evaluated the performance of 33 thermal cyclers from different manufacturers in controlled PCR and RAPD analyses. It found that temperature-calibrated cyclers consistently produced more repeatable results than non-calibrated ones, irrespective of make and model. Proper temperature calibration and monitoring are important for thermal cycler performance. Extended warranty and service are also important factors to consider when selecting a reliable unit.

1. The Fashion of Thermal Cyclers
Years ago when I was a post doctoral fellow, I did PCR with three water baths, three timers.
Quickly, all kind of thermal cyclers come to market. And the prices are constantly going down!
Our first lab paid over $10,000 for a toaster oven type, the cheapest we could afford at that time.
Now you can buy a new fancy one for less than $5K
How do different PCR machines stack up? Any scientific data? Yes, here is a short abstract:
Interlaboratory Study on Thermal Cycler Performance in
Controlled PCR and Random Amplified Polymorphic DNA
Analyses
Ginny C. Saunders1, Juliet Dukes1, Helen C. Parkes1,a and Johanne H. Cornett1
1
Life Sciences Research, LGC Ltd., Queens Road, Teddington, Middlesex, TW11 0LY, United
Kingdom.
a
Author for correspondence. Fax 44-020-89432767; hcp@lgc.co.uk.
Background: Intercomparisons of PCR-based data between laboratories require an assurance of
assay reproducibility. We performed an interlaboratory study to investigate the contribution made
by a variety of thermal cyclers to PCR performance as measured by interblock reproducibility
and intrablock repeatability.
Methods: Two standardized assays designed to minimize the introduction of non-thermal-cycler-
dependent variations were evaluated by 18 laboratories in the United Kingdom, using 33 thermal
cyclers of various makes and models. We used a single-product (590 bp) PCR, established in our
laboratory as a robust and specific reaction. The second reaction, a multiproduct random amplified
polymorphic DNA (RAPD) PCR, was known to be more susceptible to small changes in block
temperature and was therefore considered a way of assessing block uniformity with respect to
temperature. Assay repeatability data were analyzed with respect to temperature calibration
status, the type of temperature control mechanism, thermal cycler age, and the presence of oil
overlay or heated lid systems.
Results: All (100%) of the laboratories produced the correct target for the single-product PCR
assay, although substantial variation in yield in replicate reactions was observed in 9.4% of these.
The RAPD reaction generated results that varied extensively both within the same block and
between different thermal cyclers. For eight replicates of a positive sample, 88% intrablock
repeatability was demonstrated in calibrated thermal cyclers, which decreased to 63% in
noncalibrated instruments.
Conclusions: Irrespective of the make and model of thermal cycler, temperature-calibrated
instruments consistently generated more repeatable RAPD data than noncalibrated instruments.
Guidelines are offered on optimizing and monitoring thermal cycler performance.
As you can see, the light flash type offer more variations. Any other types, all the stuff pretty
much produced very similar results.

2. The key for selecting a reliable thermal cycler unit is the service and warranty. ThermoExp500
system comes with two year standard warranty!