diff --git a/cppwinrt/code_writers.h b/cppwinrt/code_writers.h
index 4b4fa8229..e24b462cb 100644
--- a/cppwinrt/code_writers.h
+++ b/cppwinrt/code_writers.h
@@ -169,7 +169,7 @@ namespace cppwinrt
 
     [[nodiscard]] static finish_with wrap_std_namespace(writer& w)
     {
-        w.write(R"(namespace std
+        w.write(R"(WINRT_EXPORT namespace std
 {
 )");
 
diff --git a/cppwinrt/cppwinrt.vcxproj b/cppwinrt/cppwinrt.vcxproj
index 0f8d398fb..f4ed40fb9 100644
--- a/cppwinrt/cppwinrt.vcxproj
+++ b/cppwinrt/cppwinrt.vcxproj
@@ -73,6 +73,7 @@
     <ClInclude Include="..\strings\base_macros.h" />
     <ClInclude Include="..\strings\base_marshaler.h" />
     <ClInclude Include="..\strings\base_meta.h" />
+    <ClInclude Include="..\strings\base_module.h" />
     <ClInclude Include="..\strings\base_natvis.h" />
     <ClInclude Include="..\strings\base_reference_produce.h" />
     <ClInclude Include="..\strings\base_reference_produce_1.h" />
diff --git a/cppwinrt/cppwinrt.vcxproj.filters b/cppwinrt/cppwinrt.vcxproj.filters
index 26c1fdafd..fe2b4ea95 100644
--- a/cppwinrt/cppwinrt.vcxproj.filters
+++ b/cppwinrt/cppwinrt.vcxproj.filters
@@ -109,6 +109,9 @@
     <ClInclude Include="..\strings\base_meta.h">
       <Filter>strings</Filter>
     </ClInclude>
+    <ClInclude Include="..\strings\base_module.h">
+      <Filter>strings</Filter>
+    </ClInclude>
     <ClInclude Include="..\strings\base_natvis.h">
       <Filter>strings</Filter>
     </ClInclude>
diff --git a/cppwinrt/main.cpp b/cppwinrt/main.cpp
index 1b26659a3..fc5cc1cb4 100644
--- a/cppwinrt/main.cpp
+++ b/cppwinrt/main.cpp
@@ -294,7 +294,7 @@ Where <spec> is one or more of:
             write_preamble(ixx);
             ixx.write("module;\n");
             ixx.write(strings::base_includes);
-            ixx.write("\nexport module winrt;\n#define WINRT_EXPORT export\n\n");
+            ixx.write(strings::base_module);
 
             for (auto&&[ns, members] : c.namespaces())
             {
diff --git a/strings/base_collections_map.h b/strings/base_collections_map.h
index f4bd74baf..1a0fe4c1e 100644
--- a/strings/base_collections_map.h
+++ b/strings/base_collections_map.h
@@ -116,7 +116,7 @@ WINRT_EXPORT namespace winrt
     }
 }
 
-namespace std
+WINRT_EXPORT namespace std
 {
     template<typename K, typename V>
     struct tuple_size<winrt::Windows::Foundation::Collections::IKeyValuePair<K, V>>
diff --git a/strings/base_coroutine_foundation.h b/strings/base_coroutine_foundation.h
index 943e640ed..3e4198eef 100644
--- a/strings/base_coroutine_foundation.h
+++ b/strings/base_coroutine_foundation.h
@@ -655,9 +655,9 @@ namespace winrt::impl
 }
 
 #ifdef __cpp_lib_coroutine
-namespace std
+WINRT_EXPORT namespace std
 #else
-namespace std::experimental
+WINRT_EXPORT namespace std::experimental
 #endif
 {
     template <typename... Args>
diff --git a/strings/base_coroutine_threadpool.h b/strings/base_coroutine_threadpool.h
index 4ea37bf75..81e5cee6d 100644
--- a/strings/base_coroutine_threadpool.h
+++ b/strings/base_coroutine_threadpool.h
@@ -1,6 +1,20 @@
 
 namespace winrt::impl
 {
+#ifdef __cpp_lib_coroutine
+    template <typename T = void>
+    using coroutine_handle = std::coroutine_handle<T>;
+
+    using suspend_always = std::suspend_always;
+    using suspend_never = std::suspend_never;
+#else
+    template <typename T = void>
+    using coroutine_handle = std::experimental::coroutine_handle<T>;
+
+    using suspend_always = std::experimental::suspend_always;
+    using suspend_never = std::experimental::suspend_never;
+#endif
+
     inline auto submit_threadpool_callback(void(__stdcall* callback)(void*, void* context), void* context)
     {
         if (!WINRT_IMPL_TrySubmitThreadpoolCallback(callback, context, nullptr))
@@ -676,9 +690,9 @@ WINRT_EXPORT namespace winrt
 }
 
 #ifdef __cpp_lib_coroutine
-namespace std
+WINRT_EXPORT namespace std
 #else
-namespace std::experimental
+WINRT_EXPORT namespace std::experimental
 #endif
 {
     template <typename... Args>
diff --git a/strings/base_includes.h b/strings/base_includes.h
index 7354a304c..307f06ba2 100644
--- a/strings/base_includes.h
+++ b/strings/base_includes.h
@@ -25,29 +25,7 @@
 #endif
 
 #ifdef __cpp_lib_coroutine
-
 #include <coroutine>
-
-namespace winrt::impl
-{
-    template <typename T = void>
-    using coroutine_handle = std::coroutine_handle<T>;
-
-    using suspend_always = std::suspend_always;
-    using suspend_never = std::suspend_never;
-}
-
 #else
-
 #include <experimental/coroutine>
-
-namespace winrt::impl
-{
-    template <typename T = void>
-    using coroutine_handle = std::experimental::coroutine_handle<T>;
-
-    using suspend_always = std::experimental::suspend_always;
-    using suspend_never = std::experimental::suspend_never;
-}
-
 #endif
diff --git a/strings/base_macros.h b/strings/base_macros.h
index 92f746699..d78961f86 100644
--- a/strings/base_macros.h
+++ b/strings/base_macros.h
@@ -39,6 +39,8 @@
 #define _WINDOWS_NUMERICS_NAMESPACE_ winrt::Windows::Foundation::Numerics
 #define _WINDOWS_NUMERICS_BEGIN_NAMESPACE_ WINRT_EXPORT namespace winrt::Windows::Foundation::Numerics
 #define _WINDOWS_NUMERICS_END_NAMESPACE_
+// the include in purview of a module is intentional, we want to export the numeric types as part of the module
+#pragma warning(suppress: 5244)
 #include <WindowsNumerics.impl.h>
 #undef _WINDOWS_NUMERICS_NAMESPACE_
 #undef _WINDOWS_NUMERICS_BEGIN_NAMESPACE_
diff --git a/strings/base_module.h b/strings/base_module.h
new file mode 100644
index 000000000..2dc1e4c93
--- /dev/null
+++ b/strings/base_module.h
@@ -0,0 +1,10 @@
+
+// Since modules don't result in global symbol pollution,
+// we can always enable the classic COM support.
+// Users will have to include headers declaring these interfaces
+// to make use of it.
+#include <Unknwn.h>
+#undef GetCurrentTime // Get rid of this evil macro
+
+export module winrt;
+#define WINRT_EXPORT export
diff --git a/strings/base_std_hash.h b/strings/base_std_hash.h
index eb97db0e9..9767e11cf 100644
--- a/strings/base_std_hash.h
+++ b/strings/base_std_hash.h
@@ -32,7 +32,7 @@ namespace winrt::impl
     };
 }
 
-namespace std
+WINRT_EXPORT namespace std
 {
     template<> struct hash<winrt::hstring>
     {
diff --git a/test/test_cpp20/async.cpp b/test/test_cpp20/async.cpp
new file mode 100644
index 000000000..129e71080
--- /dev/null
+++ b/test/test_cpp20/async.cpp
@@ -0,0 +1,98 @@
+#include <chrono>
+#include <Windows.h>
+
+#include "catch.hpp"
+
+import winrt;
+
+using namespace winrt;
+using namespace Windows::Foundation;
+using namespace std::chrono_literals;
+
+namespace
+{
+    //
+    // Just some quick tests to make sure that coroutines compile and work with C++20 modules.
+    // Taken from async_throw in test
+    // IAsyncOperation and IAsyncOperationWithProgress are affected by compiler bugs so disabled for now:
+    // https://developercommunity.visualstudio.com/t/identifier-not-found-with-default-membe/1376824
+    //
+
+    IAsyncAction Action()
+    {
+        co_await 10ms;
+        throw hresult_invalid_argument(L"Async");
+    }
+
+    IAsyncActionWithProgress<int> ActionWithProgress()
+    {
+        co_await 10ms;
+        throw hresult_invalid_argument(L"Async");
+    }
+
+#if 0
+    IAsyncOperation<int> Operation()
+    {
+        co_await 10ms;
+        throw hresult_invalid_argument(L"Async");
+        co_return 1;
+    }
+
+    IAsyncOperationWithProgress<int, int> OperationWithProgress()
+    {
+        co_await 10ms;
+        throw hresult_invalid_argument(L"Async");
+        co_return 1;
+    }
+#endif
+
+    template <typename F>
+    void Check(F make)
+    {
+        try
+        {
+            make().get();
+            REQUIRE(false);
+        }
+        catch (hresult_invalid_argument const& e)
+        {
+            REQUIRE(e.message() == L"Async");
+        }
+
+        handle completed{ CreateEvent(nullptr, true, false, nullptr) };
+        auto async = make();
+
+        async.Completed([&](auto&& sender, AsyncStatus status)
+            {
+                REQUIRE(async == sender);
+                REQUIRE(status == AsyncStatus::Error);
+                SetEvent(completed.get());
+            });
+
+        REQUIRE(WaitForSingleObject(completed.get(), 1000) == WAIT_OBJECT_0);
+        REQUIRE(async.Status() == AsyncStatus::Error);
+
+        hresult_error e(async.ErrorCode(), take_ownership_from_abi);
+        REQUIRE(e.message() == L"Async");
+
+        try
+        {
+            async.GetResults();
+            REQUIRE(false);
+        }
+        catch (hresult_invalid_argument const& e)
+        {
+            REQUIRE(e.message() == L"Async");
+        }
+    }
+}
+
+TEST_CASE("async_throw")
+{
+    Check(Action);
+    Check(ActionWithProgress);
+#if 0
+    Check(Operation);
+    Check(OperationWithProgress);
+#endif
+}
diff --git a/test/test_cpp20/main.cpp b/test/test_cpp20/main.cpp
index 7873e4ee7..4b9f3f8d5 100644
--- a/test/test_cpp20/main.cpp
+++ b/test/test_cpp20/main.cpp
@@ -1,6 +1,7 @@
 #define CATCH_CONFIG_RUNNER
 #include "catch.hpp"
-#include "winrt/base.h"
+
+import winrt;
 
 using namespace winrt;
 
diff --git a/test/test_cpp20/pch.cpp b/test/test_cpp20/pch.cpp
deleted file mode 100644
index 1d9f38c57..000000000
--- a/test/test_cpp20/pch.cpp
+++ /dev/null
@@ -1 +0,0 @@
-#include "pch.h"
diff --git a/test/test_cpp20/pch.h b/test/test_cpp20/pch.h
deleted file mode 100644
index ea74230cc..000000000
--- a/test/test_cpp20/pch.h
+++ /dev/null
@@ -1,12 +0,0 @@
-#pragma once
-
-#pragma warning(4: 4458) // ensure we compile clean with this warning enabled
-
-#define WINRT_LEAN_AND_MEAN
-#include <unknwn.h>
-#include "winrt/Windows.Foundation.Collections.h"
-#include "winrt/Windows.Foundation.Numerics.h"
-#include <winstring.h>
-#include "catch.hpp"
-
-using namespace std::literals;
diff --git a/test/test_cpp20/ranges.cpp b/test/test_cpp20/ranges.cpp
index 9bf88a579..a53fb00fe 100644
--- a/test/test_cpp20/ranges.cpp
+++ b/test/test_cpp20/ranges.cpp
@@ -1,7 +1,10 @@
-#include "pch.h"
 #include <algorithm>
 #include <ranges>
 
+#include "catch.hpp"
+
+import winrt;
+
 TEST_CASE("ranges")
 {
     {
diff --git a/test/test_cpp20/test_cpp20.vcxproj b/test/test_cpp20/test_cpp20.vcxproj
index 485218a0f..828d45acf 100644
--- a/test/test_cpp20/test_cpp20.vcxproj
+++ b/test/test_cpp20/test_cpp20.vcxproj
@@ -131,6 +131,8 @@
       <PreprocessorDefinitions>NOMINMAX;_MBCS;%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <RuntimeLibrary>MultiThreaded</RuntimeLibrary>
       <LanguageStandard>stdcpplatest</LanguageStandard>
+      <PrecompiledHeader>NotUsing</PrecompiledHeader>
+      <AdditionalOptions>/bigobj</AdditionalOptions>
     </ClCompile>
     <Link>
       <SubSystem>Console</SubSystem>
@@ -153,6 +155,8 @@
       <PreprocessorDefinitions>NOMINMAX;_MBCS;%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <RuntimeLibrary>MultiThreadedDebug</RuntimeLibrary>
       <LanguageStandard>stdcpplatest</LanguageStandard>
+      <PrecompiledHeader>NotUsing</PrecompiledHeader>
+      <AdditionalOptions>/bigobj</AdditionalOptions>
     </ClCompile>
     <Link>
       <SubSystem>Console</SubSystem>
@@ -173,6 +177,8 @@
       <PreprocessorDefinitions>NOMINMAX;_MBCS;%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <RuntimeLibrary>MultiThreadedDebug</RuntimeLibrary>
       <LanguageStandard>stdcpplatest</LanguageStandard>
+      <PrecompiledHeader>NotUsing</PrecompiledHeader>
+      <AdditionalOptions>/bigobj</AdditionalOptions>
     </ClCompile>
     <Link>
       <SubSystem>Console</SubSystem>
@@ -193,6 +199,8 @@
       <PreprocessorDefinitions>NOMINMAX;_MBCS;%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <RuntimeLibrary>MultiThreadedDebug</RuntimeLibrary>
       <LanguageStandard>stdcpplatest</LanguageStandard>
+      <PrecompiledHeader>NotUsing</PrecompiledHeader>
+      <AdditionalOptions>/bigobj</AdditionalOptions>
     </ClCompile>
     <Link>
       <SubSystem>Console</SubSystem>
@@ -213,6 +221,8 @@
       <PreprocessorDefinitions>NOMINMAX;_MBCS;%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <RuntimeLibrary>MultiThreadedDebug</RuntimeLibrary>
       <LanguageStandard>stdcpplatest</LanguageStandard>
+      <PrecompiledHeader>NotUsing</PrecompiledHeader>
+      <AdditionalOptions>/bigobj</AdditionalOptions>
     </ClCompile>
     <Link>
       <SubSystem>Console</SubSystem>
@@ -235,6 +245,8 @@
       <PreprocessorDefinitions>NOMINMAX;_MBCS;%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <RuntimeLibrary>MultiThreaded</RuntimeLibrary>
       <LanguageStandard>stdcpplatest</LanguageStandard>
+      <PrecompiledHeader>NotUsing</PrecompiledHeader>
+      <AdditionalOptions>/bigobj</AdditionalOptions>
     </ClCompile>
     <Link>
       <SubSystem>Console</SubSystem>
@@ -259,6 +271,8 @@
       <PreprocessorDefinitions>NOMINMAX;_MBCS;%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <RuntimeLibrary>MultiThreaded</RuntimeLibrary>
       <LanguageStandard>stdcpplatest</LanguageStandard>
+      <PrecompiledHeader>NotUsing</PrecompiledHeader>
+      <AdditionalOptions>/bigobj</AdditionalOptions>
     </ClCompile>
     <Link>
       <SubSystem>Console</SubSystem>
@@ -283,6 +297,8 @@
       <PreprocessorDefinitions>NOMINMAX;_MBCS;%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <RuntimeLibrary>MultiThreaded</RuntimeLibrary>
       <LanguageStandard>stdcpplatest</LanguageStandard>
+      <PrecompiledHeader>NotUsing</PrecompiledHeader>
+      <AdditionalOptions>/bigobj</AdditionalOptions>
     </ClCompile>
     <Link>
       <SubSystem>Console</SubSystem>
@@ -299,15 +315,9 @@
     </PostBuildEvent>
   </ItemDefinitionGroup>
   <ItemGroup>
-    <ClInclude Include="pch.h" />
-  </ItemGroup>
-  <ItemGroup>
-    <ClCompile Include="main.cpp">
-      <PrecompiledHeader>NotUsing</PrecompiledHeader>
-    </ClCompile>
-    <ClCompile Include="pch.cpp">
-      <PrecompiledHeader>Create</PrecompiledHeader>
-    </ClCompile>
+    <ClCompile Include="$(CppWinRTDir)winrt\winrt.ixx" />
+    <ClCompile Include="async.cpp" />
+    <ClCompile Include="main.cpp" />
     <ClCompile Include="ranges.cpp" />
   </ItemGroup>
   <Import Project="$(VCTargetsPath)\Microsoft.Cpp.targets" />