What is green hosting? Sus­tain­able web hosting explained

Green hosting aims to reduce the en­vi­ron­men­tal impact of web hosting. Alongside renewable elec­tric­i­ty, energy and water ef­fi­cien­cy, in­fra­struc­ture uti­liza­tion, waste heat recovery, hardware man­age­ment and trans­par­ent emissions data all play an important role.

Key Takeaways ⓘ

Green hosting goes beyond renewable elec­tric­i­ty. These are the key points for assessing sus­tain­able web hosting:

• Renewable elec­tric­i­ty is a key pre­req­ui­site, but an in­ef­fi­cient data center can still consume excessive amounts of energy and require sig­nif­i­cant quan­ti­ties of water.
• Seven key criteria help you assess a provider: renewable energy, energy ef­fi­cien­cy, cooling and water, waste heat, hardware lifecycle, emissions trans­paren­cy, and man­age­ment and mon­i­tor­ing.
• Metrics such as PUE, WUE, ERF and REF make data centers com­pa­ra­ble.
• Cer­ti­fi­ca­tions and en­vi­ron­men­tal labels can help you assess the sus­tain­abil­i­ty of green web hosting services.
• A checklist and three test cases show how to check claims such as “100% green elec­tric­i­ty” or “climate-neutral hosting.”

What exactly is green hosting?

Green hosting refers to web hosting services where providers take sys­tem­at­ic steps to reduce the en­vi­ron­men­tal impact of their data centers. Key measures include:

• Using elec­tric­i­ty from renewable sources, such as wind, solar and hy­dropow­er
• Using energy-efficient servers and data center in­fra­struc­ture
• Op­ti­miz­ing cooling systems to reduce energy con­sump­tion
• Reducing water con­sump­tion in cooling and daily op­er­a­tions
• Re­cov­er­ing and reusing waste heat, for example to heat buildings
• Procuring hardware sus­tain­ably, extending its lifespan and disposing of it re­spon­si­bly

Green hosting is therefore a branch of Green IT. While Green IT covers the en­vi­ron­men­tal impact of in­for­ma­tion and com­mu­ni­ca­tion tech­nol­o­gy as a whole, green hosting (also known as green server hosting) focuses on the in­fra­struc­ture used to run websites, ap­pli­ca­tions and other online services.

The topic is becoming in­creas­ing­ly important. According to the In­ter­na­tion­al Energy Agency (IEA), global elec­tric­i­ty con­sump­tion by data centers rose by 17 percent in 2025. Data centers spe­cial­iz­ing in AI saw an even sharper increase of around 50 percent. The IEA expects global data center elec­tric­i­ty con­sump­tion to reach ap­prox­i­mate­ly 950 TWh by 2030, almost double the 485 TWh recorded in 2025. Con­sump­tion by AI data centers could triple over the same period.

Although more efficient hardware and software reduce the energy required for in­di­vid­ual computing tasks, demand for computing power continues to grow, driven by tech­nolo­gies such as gen­er­a­tive AI, video gen­er­a­tion and AI agents.

Green hosting goes beyond renewable elec­tric­i­ty

Elec­tric­i­ty from renewable energy sources is a key pre­req­ui­site for climate-friendly hosting. However, even when powered by renewable elec­tric­i­ty, an in­ef­fi­cient data center can still consume excessive amounts of energy and require sig­nif­i­cant quan­ti­ties of water, hardware and other resources.

In Canada, Renewable Energy Cer­tifi­cates (RECs) and provin­cial clean energy credits provide evidence that elec­tric­i­ty has been generated from renewable sources. Each cer­tifi­cate typically rep­re­sents the renewable energy at­trib­ut­es of one megawatt-hour of elec­tric­i­ty generated and delivered to the grid. Or­ga­ni­za­tions can use them to sub­stan­ti­ate renewable elec­tric­i­ty claims, provided they hold the cor­re­spond­ing rights. However, pur­chas­ing cer­tifi­cates does not nec­es­sar­i­ly mean that renewable elec­tric­i­ty is supplied directly to a data center at all times.

It is therefore worth taking a closer look for com­par­i­son:

• Does a data center produce renewable elec­tric­i­ty itself?
• Are there long-term elec­tric­i­ty supply contracts or power purchase agree­ments (PPAs) in place?
• Are Renewable Energy Cer­tifi­cates (RECs) and other evidence of renewable elec­tric­i­ty pro­cure­ment disclosed trans­par­ent­ly?

The source of the elec­tric­i­ty should be assessed alongside energy ef­fi­cien­cy, water con­sump­tion, waste heat recovery and emissions data.

7 key criteria for sus­tain­able web hosting

You can assess how sus­tain­ably a hosting provider operates by looking at several key criteria.

Efficient cooling plays a special role in green web hosting. Servers convert a large part of the elec­tri­cal energy they draw into heat. Depending on the location and technical setup, outside air, optimized airflow or liquid cooling can be used, for example. At the same time, the heat from a data center can be used for buildings, heating networks or in­dus­tri­al processes.

The hardware itself is also part of the en­vi­ron­men­tal balance. The man­u­fac­ture of servers, storage and network com­po­nents requires raw materials and energy. Providers can reduce the impact by using com­po­nents for as long as possible, repairing or upgrading devices, and reusing or properly recycling de­com­mis­sioned hardware.

How are energy con­sump­tion and emissions measured?

For a mean­ing­ful com­par­i­son, hosting providers should go beyond general en­vi­ron­men­tal com­mit­ments and publish mea­sur­able per­for­mance data. Es­tab­lished data center metrics include PUE, WUE, ERF and REF.

PUE is one of the most widely used metrics. For example, if a data center’s IT equipment consumes 9,600 MWh of elec­tric­i­ty per year and the entire facility, including cooling and power supply, consumes 12,000 MWh, the PUE is 1.25. This means that for every 1 kWh consumed by the IT equipment, an ad­di­tion­al 0.25 kWh is used to power the sup­port­ing in­fra­struc­ture.

Water con­sump­tion can also be compared directly. If the example data center uses 9,600 MWh of IT energy per year and 960 cubic meters of water, this results in a WUE of 0.1 liters per kWh of IT energy. Cooling tech­nol­o­gy with low power con­sump­tion is therefore not au­to­mat­i­cal­ly the most en­vi­ron­men­tal­ly friendly solution if it causes high water demand.

For green­house gases, providers can indicate not only energy con­sump­tion but also CO₂ equiv­a­lents (CO₂e). Scope 1 emissions arise, for example, from fuels for emergency gen­er­a­tors or re­frig­er­ant losses, while Scope 2 covers indirect emissions from purchased energy.

Cer­tifi­cates and legal re­quire­ments

Cer­ti­fi­ca­tions and en­vi­ron­men­tal labels can help you assess the sus­tain­abil­i­ty of green web hosting services. They provide evidence of renewable energy use, en­vi­ron­men­tal man­age­ment practices and data center ef­fi­cien­cy.

In Canada, there is no single federal energy ef­fi­cien­cy standard that applies to all privately operated data centers. However, provin­cial and local reg­u­la­tions may establish re­quire­ments for data center de­vel­op­ment and operation.

En­vi­ron­men­tal claims made by hosting providers are subject to the Com­pe­ti­tion Act. The Com­pe­ti­tion Bureau’s guide­lines on en­vi­ron­men­tal claims explain how companies should sub­stan­ti­ate such claims.

Cer­ti­fi­ca­tions such as ISO 50001 and ISO 14001 remain useful in­di­ca­tors of a provider’s approach to energy and en­vi­ron­men­tal man­age­ment.

Checklist for comparing hosting providers

When choosing a green hosting provider, the following questions can help you assess its en­vi­ron­men­tal cre­den­tials:

✓ Can the provider demon­strate that its elec­tric­i­ty comes from renewable sources?

✓ Are RECs or on-site renewable elec­tric­i­ty gen­er­a­tion trans­par­ent­ly doc­u­ment­ed and in­de­pen­dent­ly ver­i­fi­able?

✓ Does the provider publish a measured PUE value and specify the reporting year?

✓ Does the provider provide in­for­ma­tion on water con­sump­tion or WUE?

✓ Is waste heat from the data center recovered and reused?

✓ Does the provider publish its Scope 1 and Scope 2 emissions and explain how they are cal­cu­lat­ed?

✓ How long is hardware used, and how is it handled at the end of its lifespan?

✓ Are the provider’s energy or en­vi­ron­men­tal man­age­ment systems in­de­pen­dent­ly certified?

✓ Do its sus­tain­abil­i­ty claims also cover out­sourced or colo­ca­tion data centers?

✓ Are sus­tain­abil­i­ty reports and per­for­mance metrics regularly updated and publicly available?

Test case 1: “100% green elec­tric­i­ty”

A hosting provider ad­ver­tis­es that it operates its data centers with 100 percent renewable energy. First, check whether the provider explains how the elec­tric­i­ty is procured. RECs represent renewable elec­tric­i­ty gen­er­a­tion at­trib­ut­es. The in­for­ma­tion becomes more mean­ing­ful if PUE values, elec­tric­i­ty con­sump­tion and, where ap­plic­a­ble, the provider’s own gen­er­a­tion plants or long-term power purchase agree­ments are also doc­u­ment­ed.

Test case 2: Low PUE value

Two providers publish a PUE of 1.25. This does not au­to­mat­i­cal­ly mean that both data centers operate equally sus­tain­ably. Also check the reference year, the mea­sure­ment method and the location, as well as key figures on water con­sump­tion. A low PUE can, for example, be achieved with a cooling tech­nol­o­gy that requires com­par­a­tive­ly large amounts of water.

Test case 3: “Climate-neutral hosting”

A provider describes its hosting as climate-neutral but does not publish any emissions data of its own. Check whether Scope 1 and Scope 2 emissions are reported and which ac­count­ing method the claim is based on. It should also be clear whether emissions are actually reduced or merely offset through climate pro­tec­tion projects. Without such in­for­ma­tion, the claim can only be compared to a limited extent.

Green hosting in practice at IONOS

IONOS protects the en­vi­ron­ment, among other things by operating its own data centers with 100 percent elec­tric­i­ty from renewable energies for many years. The 2025 Sus­tain­abil­i­ty Report shows a weighted PUE of 1.37 for the data centers. The energy and en­vi­ron­men­tal man­age­ment systems in ac­cor­dance with ISO 50001 and ISO 14001 fully cover the company’s own data centers.

Water and resource ef­fi­cien­cy are also recorded using specific key figures. For 2025, IONOS reports a WUE of 0.00003 liters per kWh. In addition, 93 percent of waste from the data centers was recycled or reused. Three of the nine in-house data centers also generated pho­to­volta­ic power on site in 2025 and together produced 2.8 GWh of renewable energy.

Fre­quent­ly asked questions about green hosting

Does hosting with 100 percent green elec­tric­i­ty au­to­mat­i­cal­ly count as green hosting?

No. Renewable elec­tric­i­ty is an essential criterion, but on its own it is not enough for a com­pre­hen­sive sus­tain­abil­i­ty as­sess­ment of green hosting. Energy ef­fi­cien­cy, cooling, water con­sump­tion, waste heat recovery, hardware lifespan and trans­par­ent emissions data are also essential to sus­tain­able web hosting.

What is a good PUE value?

As a general rule, the closer the PUE is to 1.0, the lower the ad­di­tion­al energy con­sump­tion for cooling, power supply and other in­fra­struc­ture. However, there is no universal threshold value that applies to every data center. Location, uti­liza­tion, age and mea­sure­ment method must be taken into account when making com­par­isons.

Is shared hosting more sus­tain­able than having your own server?

Shared hosting can make better use of existing hardware because several customers share one physical server. This can reduce the resource re­quire­ments per ap­pli­ca­tion. However, whether the overall offering is more sus­tain­able also depends on the data center’s elec­tric­i­ty source, ef­fi­cien­cy, cooling and hardware man­age­ment.

Can a website itself become more sus­tain­able?

Yes. Green hosting is only one part of a website’s en­vi­ron­men­tal footprint. Fewer data transfers, optimized images, efficient code and a lean technical ar­chi­tec­ture also reduce resource con­sump­tion. These ap­proach­es are grouped under the terms green web design and green coding.