Choosing a high and low temperature test chamber is not simply a matter of comparing temperature ranges, chamber capacities, or prices.
Two chambers may both be rated from -70°C to +150°C, yet perform very differently once a real specimen is placed inside.
The correct chamber depends on what you are testing, how large and heavy the specimen is, whether it generates heat, how quickly its temperature must change, which test method applies, and how the equipment will be installed in your laboratory.
For procurement teams and reliability engineers, the most useful selection principle is simple:
Start with the test requirement. End with the chamber model.
This guide explains how to turn an actual test requirement into a practical chamber specification—and what to check before requesting quotations from manufacturers.
Quick Answer: How Do You Choose a High and Low Temperature Test Chamber?
A high and low temperature test chamber should be selected according to eight main factors:
- Specimen size, weight and quantity
- Required minimum and maximum temperature
- Usable test space and airflow clearance
- Specimen thermal mass and heat generation
- Required heating and cooling performance
- Applicable test standards
- Safety and monitoring requirements
- Laboratory installation conditions
Do not select a chamber only because the specimen physically fits inside or because the machine reaches a lower temperature than competing models.
The chamber must be capable of reproducing the actual environmental conditions required by the test while the real test load is inside.
Define the Specimen Before Comparing Chambers
Before looking at chamber specifications, define what will actually be placed inside.
At minimum, collect the following information:
| Item | Information to Confirm |
|---|---|
| Specimen | PCB, ECU, sensor, connector, battery component, plastic part, assembly, etc. |
| Dimensions | Maximum W × H × D |
| Quantity | Number of specimens per batch |
| Weight | Individual and total test load |
| Material | Metal, plastic, rubber, electronics or mixed assembly |
| Operating state | Powered or unpowered |
| Heat generation | Approximate heat produced during operation |
| Connections | Power, thermocouples, sensors, communication or data cables |
| Fixture | Shelf, rack, tray, jig or mounting structure |
Why does this matter?
Because a chamber is not cooling and heating empty air during a real test.
It is controlling the temperature of an environment containing the specimen, fixture, shelves, cables and any heat generated by powered products.
For example, testing several small unpowered sensors presents a very different thermal load from testing a powered automotive control module, even if both fit inside the same chamber.
Better RFQ information
Instead of sending a supplier:
“Please quote a 408 L chamber from -40°C to +150°C.”
A more useful request would be:
“We need to test six electronic assemblies measuring approximately X × Y × Z mm, with a total test load of XX kg. The required temperature range is -40°C to +125°C, and the specimens will be powered during part of the test.”
The second request gives the chamber manufacturer enough information to evaluate the actual configuration.
Choose the Required Temperature Range
Temperature range is usually the first specification buyers compare.
Common chamber configurations may include:
- -20°C to +150°C
- -40°C to +150°C
- -70°C to +150°C
The lowest available temperature, however, is not automatically the best choice.
Suppose your qualification procedure requires:
-40°C → +85°C
A -70°C chamber provides additional capability, but that additional capability should have a practical reason.
It may be useful when:
- future programs may require lower temperatures;
- several product families will share the chamber;
- customer specifications require lower-temperature testing;
- engineering teams need additional margin for development testing.
If none of these conditions apply, purchasing substantially more refrigeration capability than the test requires may increase system complexity and investment without improving the required test.
Use this selection sequence
Required Test Temperature → Reasonable Operating Margin → Chamber Configuration
Not:
Lowest Available Chamber Temperature → Test Requirement
Temperature Range Does Not Tell You the Whole Story
Consider two chambers with the same advertised range:
-40°C to +150°C
They are not necessarily equivalent.
Temperature range tells you where the chamber can operate.
It does not tell you:
- how quickly temperature changes;
- how stable the controlled condition is;
- how evenly temperature is distributed;
- how the chamber behaves with a test load inside;
- how much heat from powered specimens the refrigeration system can compensate.
For repeatable environmental testing, buyers should therefore evaluate specifications such as:
Temperature Fluctuation
How much the controlled temperature varies around the target condition over time.
Temperature Uniformity
How consistent the temperature field is across different locations in the working space.
Temperature Deviation
How closely the measured chamber condition corresponds to the required temperature condition.
These parameters matter because specimens positioned in different areas of the chamber should experience controlled and repeatable test conditions.
Choose Chamber Capacity by Usable Test Space — Not Liters Alone
Capacity is one of the easiest specifications to misunderstand.
Chambers may be offered in sizes such as:
100 L / 150 L / 225 L / 408 L / 800 L / 1000 L
But chamber selection should not be based on liters alone.
The important question is:
How much usable test space remains after the specimen, fixture, cables and airflow clearance are considered?
A specimen can physically fit inside a chamber and still be too large for a good test arrangement.
If it occupies most of the working space, it may restrict conditioned-air circulation around the specimen.
The same problem can occur when many small samples are packed too closely together.
Typical GDW Size Options
| Model | Capacity | Internal Dimensions (W × H × D) |
|---|---|---|
| GDW-100 | 100 L | 400 × 500 × 500 mm |
| GDW-150 | 150 L | 500 × 600 × 500 mm |
| GDW-225 | 225 L | 500 × 750 × 600 mm |
| GDW-408 | 408 L | 600 × 850 × 800 mm |
| GDW-800 | 800 L | 1000 × 1000 × 800 mm |
| GDW-1000 | 1000 L | 1000 × 1000 × 1000 mm |
The internal W × H × D dimensions are often more useful for initial selection than the nominal liter value.
A long automotive component, for example, may require a larger chamber despite having relatively little total volume.
Multiple electronic assemblies may also require additional space so that air can circulate between individual specimens.
The exact required clearance depends on the chamber design, specimen geometry and test arrangement.
Instead of relying on a universal percentage rule, provide the manufacturer with a drawing or dimensions of the proposed load arrangement and confirm that the chamber has sufficient usable working space.
Calculate the Real Test Load
Chamber volume is only part of the selection problem.
The chamber also has to change the temperature of everything placed inside it.
That may include:
- specimens;
- metal fixtures;
- trays;
- shelves;
- wiring;
- instrumentation;
- mounting structures.
This creates thermal mass.
Consider two laboratories using the same 408 L chamber.
Laboratory A
Tests several small, unpowered electronic sensors.
Laboratory B
Tests a heavy metal electronic assembly mounted on a fixture while the product operates and generates heat.
The chamber volume is identical.
The thermal demand is not.
This is why the total test load should be considered during chamber selection.
Powered Specimens Need Special Attention
When electronic products operate inside the chamber, they can continuously release heat.
The refrigeration system must remove this additional heat while maintaining the required low-temperature condition.
Therefore, tell the manufacturer:
- whether the specimen is powered;
- how many specimens operate simultaneously;
- approximate power consumption;
- estimated heat dissipation;
- when the load operates during the test profile.
A chamber capable of reaching -40°C when empty does not automatically guarantee the same dynamic performance with a substantial internal heat load.
Determine the Required Heating and Cooling Performance
Buyers often ask:
“What is the cooling rate?”
A better question is:
“Under what conditions was the cooling rate measured?”
Heating and cooling performance can depend on:
- starting temperature;
- ending temperature;
- chamber volume;
- refrigeration configuration;
- ambient conditions;
- empty versus loaded operation;
- specimen thermal mass;
- heat generated by powered specimens.
Consider a test that moves from:
+85°C to -40°C
The temperature difference is:
125°C
If the transition takes 100 minutes, the average temperature-change rate is:
1.25°C/min
That is useful for understanding the programmed profile.
But it does not automatically mean that the specimen itself cools at exactly 1.25°C/min.
Chamber Air Temperature ≠ Specimen Temperature
This is one of the most important distinctions in chamber selection.
The chamber control system measures and regulates the environmental temperature.
The specimen responds thermally to that environment.
A large metal component may respond much more slowly than the surrounding air.
A lightweight PCB may respond faster.
Specimen temperature response depends on:
Mass · Material · Geometry · Airflow · Fixture · Internal Heat Generation
Therefore:
For temperature-sensitive qualification work, confirm whether the required ramp rate refers to chamber air temperature or actual specimen temperature. These are not necessarily interchangeable specifications.
This distinction becomes particularly important when the test requires the specimen to remain at a target condition for a defined period.
Reaching the chamber setpoint and reaching specimen thermal stabilization are not necessarily the same event.
Do You Actually Need Rapid Temperature Change?
A conventional high and low temperature chamber and a rapid temperature change chamber serve overlapping but different requirements.
If your test mainly involves:
- high-temperature exposure;
- low-temperature exposure;
- long dwell periods;
- storage testing;
- standard environmental qualification;
a conventional temperature chamber may be sufficient.
If the test requires repeated and controlled temperature transitions at significantly higher rates, a rapid temperature change chamber may be more appropriate.
This distinction should be made before requesting quotations.
Saying:
“We need -70°C to +150°C.”
is not enough.
The supplier also needs to know:
How quickly must the chamber move between the required temperatures?
Do not pay for high ramp-rate capability unless the test program actually needs it.
Determine Whether Humidity Control Is Required
A high and low temperature chamber primarily controls temperature.
Some test programs require:
Temperature + Relative Humidity
These are different environmental requirements.
Before purchasing, determine whether your procedure includes:
- dry heat;
- cold exposure;
- temperature cycling;
- damp heat;
- controlled relative humidity;
- combined temperature-humidity conditions.
If humidity must also be controlled, a programmable temperature and humidity chamber may be the more appropriate configuration.
Do not add humidity simply because it appears to provide more functionality.
It changes the chamber architecture and operating requirements.
Match the Chamber to the Actual Test Standard
Standards should influence chamber selection before purchase, not after installation.
Common IEC environmental temperature test methods include:
IEC 60068-2-1 — Cold
Used for cold environmental testing of specimens under defined conditions.
IEC 60068-2-2 — Dry Heat
Used for evaluating specimens under dry high-temperature conditions.
IEC 60068-2-14 — Change of Temperature
Covers specified change-of-temperature test methods.
The official publications can be checked through the IEC Webstore.
However, asking:
“Does this chamber comply with IEC 60068?”
is too broad.
IEC 60068 contains multiple environmental test methods.
A better purchasing question is:
Which test method, specimen condition, temperature profile and required performance must the chamber support?
A chamber having the required maximum and minimum temperatures does not, by itself, prove that every relevant test requirement is satisfied.
Evaluate Air Circulation and Specimen Placement
Temperature control depends not only on refrigeration and heating.
Conditioned air must circulate through the test space.
The airflow system helps distribute thermal energy around the specimens and return air to the conditioning section.
Poor specimen placement can interfere with this process.
Common problems include:
- oversized samples;
- overloaded shelves;
- specimens packed too closely;
- fixtures blocking air circulation;
- blocked supply or return paths.
This means specimen arrangement is part of test design—not simply a matter of fitting as many products as possible into the chamber.
For batch testing, discuss the intended sample arrangement with the manufacturer before finalizing chamber size.
Evaluate the Refrigeration System Under Real Test Conditions
Low-temperature capability depends heavily on refrigeration performance.
You do not need to become a refrigeration engineer to purchase a chamber, but several questions are worth asking.
Confirm:
- refrigeration architecture;
- compressor configuration;
- cooling method;
- refrigerant configuration;
- low-temperature operating capability;
- available heat compensation capacity;
- heat rejection requirements;
- maintenance access;
- laboratory ambient requirements.
The system required for -70°C operation can differ substantially from one intended primarily for moderate sub-zero testing.
Heat Compensation Matters for Powered Products
If your specimen operates during testing, ask:
How much internal heat can the chamber compensate at the required low-temperature condition?
Do not evaluate this only at room temperature.
For example, a powered electronics test may require the chamber to maintain a low environmental temperature while the products continuously generate heat.
The actual requirement therefore becomes:
Low Temperature + Internal Heat Load
rather than simply:
Low Temperature
This distinction can significantly affect refrigeration-system selection.
This is why comparing only one °C/min value across quotations can be misleading unless the measurement conditions are comparable.
Check Laboratory Installation Requirements Before Ordering
A technically suitable chamber can still become an installation problem if facility requirements are ignored.
Check these conditions before issuing the purchase order.
Power Supply
Confirm:
- voltage;
- frequency;
- phase;
- required electrical capacity.
Access Route
Check the chamber's external dimensions against:
- factory doors;
- laboratory doors;
- corridors;
- elevators;
- loading areas.
Do not compare only internal chamber dimensions.
Heat Rejection and Ventilation
Environmental chambers transfer heat somewhere.
The laboratory must be able to handle the heat rejected by the equipment according to the selected system configuration.
Service Clearance
Allow sufficient space for:
- maintenance;
- ventilation;
- component access;
- door operation.
Floor Loading
Large chambers and heavy test loads may require consideration of floor capacity.
Utilities
Depending on the selected chamber configuration, confirm whether additional water, drainage or other facility connections are required.
These questions should be resolved before delivery.
Plan Cable and Instrument Access
Many environmental tests require the specimen to remain connected to equipment outside the chamber.
Typical connections include:
- power cables;
- thermocouples;
- voltage/current monitoring;
- data acquisition;
- communication cables;
- sensor wiring.
This makes chamber access ports an important selection detail.
Before ordering, ask:
How many cables must enter the chamber?
What is the largest connector that must pass through the port?
Where should the access port be located?
Will the specimen remain connected during the entire test?
An access port that is too small or positioned poorly can create unnecessary problems during daily testing.
Evaluate the Controller Based on the Test Workflow
A touchscreen is useful, but it should not be the main reason for selecting a chamber.
The important question is:
Can the controller reproduce the required test program reliably and efficiently?
Depending on your workflow, useful functions may include:
- programmable temperature steps;
- dwell-time control;
- cycle repetition;
- multi-segment programs;
- alarm management;
- trend display;
- program storage;
- data recording;
- data export.
For laboratories running repeated qualification tests, program repeatability is particularly important.
Engineers should be able to reproduce a validated profile without rebuilding it manually every time.
Consider Safety According to the Specimen
The required chamber safety configuration depends partly on what is being tested.
An unpowered plastic specimen and an energized battery assembly do not present the same potential hazards.
Tell the chamber manufacturer if the specimen includes:
- batteries;
- energized electronics;
- combustible materials;
- pressurized components;
- potentially hazardous failure modes.
Additional safety configurations may be required depending on the specimen and test procedure.
This is especially important for battery-related testing.
A chamber having the correct temperature range does not automatically mean it is suitable for every battery test.
The following must be evaluated separately:
Specimen Hazard + Test Condition + Failure Mode + Safety Configuration
Compare Supplier Quotations Under the Same Conditions
Imagine three manufacturers all offer:
408 L | -70°C to +150°C
At first glance, the chambers appear equivalent.
They may not be.
Create a comparison sheet based on the same test requirement.
| Selection Item | Supplier A | Supplier B | Supplier C |
|---|---|---|---|
| Temperature range | |||
| Internal W × H × D | |||
| Specimen load | |||
| Powered heat load | |||
| Heating performance | |||
| Cooling performance | |||
| Cooling-rate conditions | |||
| Temperature uniformity | |||
| Temperature fluctuation | |||
| Heat compensation | |||
| Access ports | |||
| Controller | |||
| Data recording | |||
| Safety configuration | |||
| Power requirement | |||
| Warranty | |||
| Technical support |
This creates a much more meaningful comparison than evaluating price against catalog temperature range alone.
Six Common Chamber Selection Mistakes
Mistake 1 — Buying the Lowest Temperature Available
Better Approach
Match the chamber range to current and foreseeable test requirements.
Do not automatically buy -70°C capability when your actual programs stop at -40°C.
Mistake 2 — Selecting Capacity Only by Specimen Dimensions
Better Approach
Include:
Specimen + Fixture + Cables + Sample Quantity + Airflow Clearance
The product fitting inside the chamber is only the first requirement.
Mistake 3 — Comparing Cooling Rates Without Measurement Conditions
Better Approach
Ask:
- From what temperature?
- To what temperature?
- Empty or loaded?
- Average or linear rate?
- Chamber air or specimen temperature?
Without these conditions, two °C/min specifications may not represent the same performance.
Mistake 4 — Ignoring Powered Specimen Heat
Better Approach
Provide the manufacturer with estimated heat generation during operation.
This is particularly important at low temperatures.
Mistake 5 — Choosing the Chamber Before Checking the Standard
Better Approach
Define the required environmental test method and profile first.
Then determine the chamber configuration.
Mistake 6 — Ignoring the Laboratory
Better Approach
Confirm:
Power · Access · Ventilation · Heat Rejection · Service Space · Utilities
before ordering.
Practical RFQ Checklist for Buyers
Before contacting a high and low temperature chamber manufacturer, prepare this information.
| Question | Your Requirement |
|---|---|
| What product will be tested? | |
| Maximum specimen dimensions? | |
| Number of specimens per batch? | |
| Total specimen weight? | |
| Fixture dimensions and weight? | |
| Minimum temperature? | |
| Maximum temperature? | |
| Required heating rate? | |
| Required cooling rate? | |
| Required dwell time? | |
| Powered during test? | Yes / No |
| Estimated internal heat generation? | |
| Temperature only or temperature + humidity? | |
| Applicable test standard? | |
| Required access ports? | |
| External sensors/data cables? | |
| Required data recording? | |
| Laboratory power supply? | |
| Special safety requirements? |
Providing these details at the RFQ stage makes it easier for manufacturers to recommend the correct configuration and makes quotations easier to compare.
Which GDW Chamber Size Should You Choose?
For initial screening, the GDW Series can be considered according to specimen scale and batch requirements.
| Typical Requirement | Initial Capacity Direction |
|---|---|
| Small components / PCB samples | 100–225 L |
| Multiple electronic components | 225–408 L |
| Medium assemblies / automotive electronics | 408 L |
| Larger assemblies / batch testing | 800 L |
| Large specimens / higher batch capacity | 1000 L |
This table should be treated as a starting point rather than a final model recommendation.
For example, a small but very long specimen may still require a larger internal dimension.
A dense batch of small electronic products may require additional volume to maintain airflow.
A powered assembly may require more refrigeration capability even if it occupies relatively little physical space.
How ITM-LAB Configures a GDW High and Low Temperature Chamber
Instead of starting only with a catalog capacity, an appropriate GDW configuration can be evaluated around the actual test.
Five inputs are especially useful.
01 — Specimen
Dimensions, quantity, weight, material and fixture.
02 — Temperature
Required minimum and maximum test temperatures.
03 — Test Profile
Heating, cooling, dwell and cycling requirements.
04 — Thermal Load
Specimen mass, fixture mass and heat generated by powered products.
05 — Standard & Safety
Applicable test procedure and specimen-specific safety requirements.
These inputs can then be used to determine:
Temperature Range → Chamber Capacity → Refrigeration Requirement → Controller → Access → Safety Options
GDW high and low temperature chambers are available in multiple capacities from 100 L to 1000 L, with configurations reaching down to -70°C and up to +150°C, depending on the selected model and test requirement.
Typical application areas include:
- consumer electronics;
- automotive electronics;
- electronic components;
- battery and energy-storage components;
- plastics and engineering materials;
- industrial and electrical assemblies.
Final Chamber Selection Checklist
Before approving the final configuration, confirm these ten questions:
1. Does the temperature range cover the actual test profile?
2. Does the internal W × H × D provide enough usable test space?
3. Is there sufficient space for airflow around the specimen and fixture?
4. Has the total specimen and fixture mass been considered?
5. Will the specimen generate heat during operation?
6. Is the required ramp rate based on chamber air or specimen temperature?
7. Can the chamber support the applicable test method?
8. Are access ports, monitoring and data requirements included?
9. Is the safety configuration appropriate for the specimen?
10. Can the laboratory provide the required power, ventilation, access and service space?
If these questions have clear answers, the final chamber selection becomes much more reliable.
FAQ
What temperature range should I choose for a high and low temperature test chamber?
Choose a temperature range that covers the actual qualification or reliability test conditions with reasonable operating margin.
For example, if your programs require testing down to -40°C, determine whether there is a genuine future requirement for -70°C before selecting the lower-temperature configuration.
Should I choose a -40°C or -70°C temperature chamber?
The decision depends on your test standards, customer requirements and foreseeable future programs.
A -70°C chamber offers broader low-temperature capability, but that capability is valuable only when the test program requires or is likely to require it.
Is a larger temperature chamber always better?
No.
Larger chambers require more laboratory space and can involve different energy, refrigeration and installation requirements.
Choose the chamber around the actual specimen arrangement and test requirement.
How do I choose the correct chamber capacity?
Start with the maximum specimen dimensions, but also consider:
- fixture dimensions;
- number of specimens;
- wiring;
- access requirements;
- airflow clearance.
The specimen should not simply fit—it should fit without preventing the chamber from maintaining the required test environment.
What is the difference between chamber temperature and specimen temperature?
Chamber temperature represents the controlled air environment.
Specimen temperature is the actual temperature of the test object.
Because the specimen has thermal mass, its temperature may lag behind the chamber air during heating or cooling.
What does cooling rate mean in a temperature chamber?
Cooling rate describes how quickly temperature decreases over a defined temperature interval and under defined measurement conditions.
When comparing chambers, check the starting and ending temperatures, whether the chamber is loaded, and whether the rate refers to chamber air or specimen temperature.
Why does heat load matter?
Powered electronics can generate heat inside the chamber.
The refrigeration system must remove that heat while still maintaining the programmed environmental condition.
This becomes especially important during low-temperature testing.
Can batteries be tested in a standard high and low temperature chamber?
It depends on the battery type, test procedure, operating condition and potential failure hazards.
The required temperature falling within the chamber's operating range does not automatically make a standard chamber suitable for the test.
Battery applications should be evaluated according to the required safety configuration.
Which IEC standards are commonly associated with high and low temperature testing?
Common references include:
- IEC 60068-2-1 — Cold
- IEC 60068-2-2 — Dry Heat
- IEC 60068-2-14 — Change of Temperature
The exact test method and conditions should be determined according to the product's applicable qualification requirements.
Conclusion: Start With the Test, Not the Catalog
The most common mistake when purchasing a high and low temperature test chamber is starting with the machine.
A better sequence is:
Specimen → Temperature → Usable Space → Thermal Load → Rate → Standard → Safety → Facility → Chamber
This changes the purchasing conversation.
Instead of asking:
“How much is your 408 L, -70°C chamber?”
you can ask:
“Can this chamber reproduce our required temperature profile with our actual specimen load and test configuration?”
That is the question that matters.
A chamber should not be selected simply because it reaches the lowest temperature, has the largest test space, or offers the highest specification on a catalog page.
It should be selected because it can create a controlled, repeatable and appropriate test environment for the actual specimen and qualification requirement.
